Tag: Diesel Diagnosis

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Why is My Diesel Fuel Injector Sleeve Leaking? Diagnose and Repair!

Diesel Fuel Injector Sleeve

The purpose of the fuel injector sleeve in diesel engines is to provide a protective barrier between the fuel components and the coolant. The sleeve is sometimes also called an injector cup. In many diesel engines, the injector passes through the cylinder head into the combustion chamber, and the surrounding area of the head may contain coolant passages.

Fuel injector sleeve leaks can be a serious problem. It allows fuel dilution and coolant contamination, both of which can cause engine damage. Many heavy-duty diesel engines have fuel injector sleeves.

Function of a Fuel Injector Sleeve

The function of a fuel injector sleeve is to separate coolant passages from the injector bore. It also provides a mounting surface for the injectors. The precise bore and sealing surface of the sleeve allow for proper injector alignment, which ensures accurate fuel spray into the injection chamber. 

A typical fuel injector sleeve is constructed from brass, copper alloy, or steel. The sleeves are sealed with O-rings, sealant, or a press-fit. The sleeve acts as a replaceable wear surface. Instead of the fuel injector contacting the cylinder head directly, it sits inside the sleeve. If damage occurs, the sleeve can usually be replaced instead of the entire cylinder head.

 Common Symptoms of a Leaking Injector Sleeve

There are several common symptoms of a leaking fuel injector sleeve. However, the most common one is found in the coolant system. You might notice a fuel smell in the coolant or see diesel floating in the coolant reservoir. Coolant is also sometimes pushed out of the overflow bottle.

Symptoms may appear in the fuel system as well. This can include loss of fuel pressure, air in the fuel system, or an extended crank time. Performance symptoms include misfires or rough idle, white exhaust smoke, and reduced fuel economy.

In some cases, these drivability and performance issues may point to injector wear beyond the sleeve itself. Hard starts, excessive smoke, rough operation, or fuel delivery problems can all be signs that the injectors are beginning to fail.

If you’re running a Caterpillar C15 ACERT engine, understanding when injector replacement becomes necessary can help prevent additional engine damage and downtime. Read our guide on When To Replace Fuel Injectors in a Caterpillar C15 ACERT to learn the most common warning signs and what to check before failure gets worse.

 Diagnostic Tests for a Leaking Diesel Fuel Injector Sleeve

There are a few diagnostic steps you can take for a leaking diesel fuel injector sleeve. The first is a visual inspection. Check the coolant reservoir for fuel contamination, and inspect the injectors and cylinder head area for residue and wetness.

The next step to take is a cooling system pressure test. Pressurize the system with the engine off, and then observe the injector bore for coolant seepage. A fuel system leak test can check for excessive fuel returning through the injectors and show whether fuel is entering the cooling system.

A cylinder leak test checks for combustion gases entering the coolant, while dye or UV testing involves adding dye to the coolant to identify leaks at the injector sleeves.

Common Causes of Fuel Injector Sleeve Failure

There are several possible reasons for fuel injector sleeve failure. Some mechanical causes include sleeve corrosion, a cracked sleeve due to wear, or damage due to improper installation. Worn or damaged o-rings, incorrect sealant, and heat cycling deterioration can also lead to sleeve failure.

Sleeve damage might occur due to certain engine operating conditions. For example, if the engine overheats or the coolant becomes contaminated for another reason. Maintenance-related causes include incorrect injector torque, reusing damaged sleeves, and improper cleaning of the injector bore.

Engines with wet sleeves or coolant-jacketed injectors are most prone to injector sleeve leaks. These are most often found on heavy-duty engines.

Inspection Procedure (Step-by-Step)

Step 1 – Remove the injector

Carefully disconnect the fuel lines and electrical connectors (if applicable), then remove the injector hold-down hardware according to the manufacturer’s procedure. Gently extract the injector using the proper puller or removal tool to avoid damaging the injector body or disturbing the injector sleeve in the cylinder head.

Step 2 – Inspect sleeve bore

After the injector is removed, visually inspect the inside of the sleeve bore for signs of coolant, fuel residue, corrosion, or carbon buildup. Any wetness, pitting, or discoloration may indicate sleeve leakage or deterioration of the sleeve material.

Step 3 – Pressure test the cooling system with the injector removed

Install a cooling system pressure tester and pressurize the system to the engine manufacturer’s recommended pressure. Observe the exposed injector sleeve bore for coolant seepage, which would indicate a compromised sleeve or failed seal.

Step 4 – Check sleeve seating and sealing surfaces

Inspect the top lip of the sleeve and the surrounding cylinder head surface where seals or o-rings seat. Look for damage such as cracks, deformation, scoring, or erosion that could prevent the sleeve from sealing properly against the injector or cylinder head.

Diesel Fuel Injector Sleeve Repair Options

Replacing the fuel injector sleeve or sleeves is the most common repair option for damaged or failed sleeves. It’s also important to install new seals and/or o-rings at the same time. Use the correct installation tools to ensure the sleeves are installed properly. In the event that the sleeves can’t be extracted in place, you may have to remove the head.

Prevent Fuel Injector Sleeve Leaks

To prevent sleeve damage, it’s crucial to use proper injector torque procedures when replacing injectors. Correct coolant maintenance is also necessary to avoid contamination, which can damage sleeves. Always use manufacturer-approved installation tools and consider periodic fuel system inspections to catch problems early.

Key symptoms to watch for include coolant contamination and performance issues such as white exhaust smoke and difficulty starting. It’s important to diagnose this problem early, as it can cause serious engine damage if left alone.

Where to Get the Best Replacement Diesel Fuel Injector Sleeves

If you’re wondering why your diesel fuel injector sleeves are leaking, contact our experts at Highway and Heavy Parts for timely advice. We can help you diagnose this problem before it causes major damage to your engine. Our extensive catalog is also the best place to get replacement fuel injector sleeves for your rig.

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Is My Diesel Water Pump Going Bad?

New Water Pumo for Diesel Engine

Your engine’s cooling system revolves around the water pump. A diesel water pump circulates coolant to keep your engine running at the optimal temperature. Water pumps are sometimes prone to catastrophic failure. However, there are usually subtle signs and symptoms before they fail completely.

When a diesel water pump fails, it can potentially cause major engine damage. Your engine will overheat quickly, increasing the risk of a blown head gasket, cracked head, or total engine failure. That’s why it’s important to know the symptoms of a failing water pump.

Why Does a Water Pump Fail?

There are four common reasons for water pump failure. One is a bad seal between the water pump housing and the engine block. This seal can fail if it’s improperly installed or if the coolant becomes corrosive. A vehicle that isn’t driven much is also at risk for seal failure. The purpose of this seal is to prevent coolant leaks and keep excess air out of the system. The latter function is almost more important because air pockets can cause the engine to overheat and encourage corrosion.

A loose drive pulley is another common cause. Wobbling wears out the pulley bearings, which can then cause the pump to lose efficiency. That’s why it’s always important to replace the pulley at the same time as the water pump.

Belt-driven water pumps often fail due to a worn, cracked, or slipping belt. To avoid this, inspect your belts regularly for damage. A broken belt has the same potential to damage your engine as a broken water pump.

Finally, worn bearings are a common culprit. These are essential to keeping the water pump impeller moving smoothly. If they wear out, the impeller might wobble or seize. This is likely to damage the pump, but it can also affect the timing system.

Symptoms of a Failing Diesel Water Pump

Let’s take a look at how the symptoms of a failing water pump usually present. If you find a puddle of coolant under your vehicle, this could be due to worn gaskets and seals. For example, the seal mentioned above.

Another sign is deposit buildup. A leak in the water pump system will cause deposits to build up around the housing. A coolant leak might also cause pitting. Finding pitting or deposits essentially means that there’s a leak in the system.

Do you hear a whining or grinding noise when you step on the gas? This is potentially due to worn bearings or a failing pulley. There could be other reasons for this noise, but failing water pump bearings are likely if you have any of the other symptoms.

The immediate signs of water pump failure include your engine overheating and steam coming out from under your hood. This usually means your water pump has completely failed and is no longer moving coolant through your engine.

Severe overheating caused by a failing water pump can lead to much larger engine problems if it’s ignored for too long. Engines like the Detroit Diesel Series 60 are especially vulnerable to cooling-system-related damage that can contribute to issues like cracked heads, head gasket failure, and internal wear.

Our guide on Common Detroit Diesel Series 60 Issues and Failures breaks down some of the most common problems owners and repair shops run into – and what causes them.

Diagnosing a Bad Water Pump

Catastrophic water pump failure is obviously bad for your engine, so it’s incredibly important to catch it before it fails. Let’s take a look at how to do that.

Step 1 – Make a visual inspection for leaks. Check under the engine and on the engine block for signs of coolant. One key sign is coolant leaking from the weep hole on the pump body. This usually indicates a worn internal seal.

Step 2 – Check for noises. If you hear a high-pitched whining or grinding located at the front of the engine, it’s likely to be a failing water pump bearing.

Step 3 – Inspect the water pump pulley and belt. If you notice significant play or wobble in the pulley, that generally means worn bearings. Similarly, look for cracks and damage to the belt if applicable.

Step 4 – Monitor the engine temperature. If you see the gauge go up quickly or sit at an unusually high temperature, the water pump might not be circulating coolant efficiently.

Step 5 – Check heater performance. A failing pump might not push sufficient coolant into the heater core, which can lead to inconsistent or cold air coming out of the vents.

Step 6 – Pressure test the system to reveal hidden leaks that might not be obvious in a regular visual inspection.

Step 7 – Check for milky oil. If your water pump seal has failed, it might allow coolant to mix with the engine oil. This results in a milky oil residue on the dipstick or engine oil cap.

Tools for Diagnosing a Bad Water Pump

For most of the above steps, you don’t need any special tools. It simply requires visual inspection for certain symptoms. However, if you decide to do a cooling system pressure test, then you’ll need a pressure gauge and a flow meter.

To pressure test, you’ll need to attach a pressure gauge to the radiator and pump to the manufacturer’s recommended pressure. A pressure drop indicates a leak.

You can also do flow rate testing with a flow meter. Low flow rates indicate a clogged impeller or failing motor.

How To Prevent Water Pump Failure

The good news is that water pumps typically last a long time. Over 1,000,000 miles is not uncommon. However, they can fail due to issues that aren’t related to wear. These common water pump problems can be avoided with regular maintenance.

For example, it’s important to flush and refill your coolant regularly so that it doesn’t become corrosive. Use only high-quality coolant and distilled water for dilution if necessary.

Inspect belts and pulleys regularly. If you find small leaks or experience overheating symptoms, don’t ignore them. They won’t go away, so it’s important to find the cause before they become big problems.

Where to Get the Best Replacement Water Pumps

Are you experiencing overheating or other symptoms consistent with a failing water pump? If so, don’t wait for it to leave you stranded; prepare for a replacement today.

Highway and Heavy Parts has long been a leading supplier of quality diesel parts like water pumps. If you need to replace your water pump or need help diagnosing a problem with it, browse our full diesel cooling system catalog or get in touch with our team for expert advice.

FAQs: How to Diagnose a Bad Diesel Water Pump

Q: What are the most common signs of a failing diesel water pump?

A: The most common signs include coolant puddles under the vehicle, deposit or rust buildup around the pump housing, a whining or grinding noise from the front of the engine, engine overheating, and steam coming from under the hood. A heater that suddenly stops blowing warm air can also indicate the pump is no longer pushing coolant efficiently.

Q: How long does a diesel water pump typically last?

A: A well-maintained diesel water pump can last over 1,000,000 miles. However, premature failure can occur due to corroded coolant, a worn drive belt, a loose pulley, or damaged bearings — all of which can be avoided with routine maintenance and regular inspections.

Q: Can a bad water pump cause engine damage?

A: Yes — a failing or failed diesel water pump can cause serious engine damage. When the coolant stops circulating, the engine overheats rapidly, which can lead to a blown head gasket, a cracked cylinder head, or complete engine failure. Catching the symptoms early is critical to avoiding costly repairs.

Q: What causes a diesel water pump to fail prematurely?

A: The four most common causes of premature failure are: a failed seal between the pump housing and engine block (often due to corrosive coolant or improper installation), a loose or worn drive pulley, a cracked or slipping drive belt, and worn internal bearings. Keeping your coolant fresh and belts/pulleys inspected goes a long way toward preventing early failure.

Q: What is the weep hole on a water pump, and why does it matter?

A: The weep hole is a small opening in the water pump body designed to allow coolant or condensation to escape when the internal seal begins to wear. If you see coolant dripping or crusted residue at the weep hole, it’s a clear early warning sign that the pump’s internal seal is failing, and replacement should be planned soon.

Q: Can I still drive my diesel if the water pump is going bad?

A: It depends on how far along the failure is. Early symptoms like minor leaks or occasional noise may allow for short-term operation, but driving with a failing pump risks rapid overheating and catastrophic engine damage. It’s strongly recommended to address the issue as soon as symptoms appear rather than waiting for complete failure.

Q: Where can I find a replacement water pump for my diesel engine?

A: Highway and Heavy Parts carries over 400 diesel cooling system parts, including water pumps for Cummins, Caterpillar, Detroit Diesel, International/Navistar, Mack, Volvo, Paccar, and more. You can browse the full cooling system catalog here or call their team of diesel experts at 844-304-7688 for help finding the right part for your engine.

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Bad Diesel Injector Symptoms: How to Diagnose a Failing Fuel Injector

A bad diesel fuel injector is likely to cause a variety of symptoms that should help you narrow it down. Some of the main symptoms include poor fuel economy, rough idling, difficulty starting, and excessive exhaust smoke. A modern vehicle should also display a warning light, which might be just a check engine light.

Some of these symptoms can also intersect with other problems, so narrowing them down to indicate a bad diesel fuel injector involves carefully investigating several issues, including exhaust smells, engine sounds, and overall performance. A diagnostic tool can help give you a firm conclusion as well.

Bad Diesel Injector Symptoms

To figure out whether you have a bad injector or another problem, it’s important to look at all the symptoms together. Let’s take a look at the various symptoms by category. The more that match up with your problem, the more likely it is to be a bad fuel injector. A bad injector causes uneven fuel delivery, which results in some or all of the symptoms discussed below.

Performance and Starting Problems

 Many of the symptoms of a failing injector or injectors come in the form of performance and starting problems. One of the most common is a rough idle or misfires. When this happens, the engine seems to shake or stumble, running unevenly at rest due to inconsistent fuel delivery. If you have a tachometer, you might notice the needle moving a lot and dipping down below normal.

Another issue is hard starting. In this case, you’ll experience longer cranking, or the engine might fail to start at all. This is especially noticeable when it’s cold. When the vehicle is in motion, you might notice loss of power, such as sluggish acceleration, bogging down on hills, or stumbling. The engine might also cut out unexpectedly.

Exhaust Look and Smell

Another area to look at when you’re trying to diagnose a bad fuel injector is the exhaust. You’re likely to notice excessive smoke, and it might be different colors from the usual gray. Black smoke indicates too much fuel, while white indicates unburned fuel passing through. Blue smoke can indicate burning oil, but it might be linked to bad injectors if they’re washing oil off the cylinder walls. A strong fuel smell is also common.

Sounds and Warning Lights

There are also sounds and warning lights associated with failing fuel injectors. Engine knocking or pinging is a common sound that is caused by bulk delivery of fuel instead of the usual fine mist. In most cases, failing injectors will also trigger a check engine light to let you know that something has gone wrong. Once you’ve confirmed multiple symptoms and there’s a CEL present, it’s time to diagnose the problem and find out if one or more bad injectors are the culprit.

How to Diagnose a Bad Diesel Fuel Injector

The easiest way to diagnose a bad diesel fuel injector is to use an OBD-II scanner for light-duty trucks made from 1997 on. Specialized diagnostic equipment, such as the J1939 protocol, for medium-duty and heavy-duty trucks and equipment. Both look for diagnostic trouble codes, but scanners won’t tell you exactly what’s wrong; you can use the codes they give to narrow down the possibilities. Another method is to inspect the engine for leaks. Look for wet spots and a diesel smell near the injectors. Modern diesel systems can show injector balance/return rates through diagnostic tools.

Tools For Diagnosing a Bad Injector

 Let’s take a closer look at the tools for diagnosing a bad diesel fuel injector. As mentioned above, the easiest way is to use a code scanning tool (OBD-II or J1939 Protocol scanners). You can also use a digital multimeter to measure injector electrical resistance and a mechanic’s stethoscope to listen for injector clicking. To measure fuel delivery and pressure, you’ll need a fuel pressure gauge and a fuel return line kit. A compression test can help you rule out other mechanical engine issues that cause the symptoms we’ve discussed.

Fuel Injector Diagnostic Steps

Step 1 – In the initial check, use the stethoscope to listen for a steady click. No click or an unusual sound suggests failure. Look for fuel leaks, wet spots, or clean streaks around the injectors.

Step 2 – Use the proper scanning tool for your diesel engine to reveal diagnostic trouble codes for misfires or fuel pressure. You can also do a cylinder isolation test. With the engine idling, disable one injector at a time. If the injector is good, it will cause the RPM to drop. If the RPM doesn’t change significantly, then the injector is likely bad.

Step 3 – Use the multimeter to check injector resistance against manufacturer specs. If you get a reading that’s way off, it indicates an electrical fault. You can also use a scan tool to check if each cylinder is producing equal power and balanced fuel delivery. A large deviation likely means a bad injector.

Step 4 – The most accurate method used by professional shops is a bench test with specialized equipment to simulate real-world conditions and check spray patterns, pressure, and flow.

Where To Get the Best Replacement Diesel Injectors

Does your diesel engine have the above signs? Don’t wait until it gets worse. At Highway and Heavy Parts, we have an expansive range of high-quality diesel engine parts for various makes and models. Our diesel experts are standing by to help you diagnose any issues you might have with bad diesel fuel injectors. Contact us today for assistance and find the best replacement injectors in our catalog. Highway and Heavy Parts is here to ensure that you have the parts and knowledge to keep your diesel engine running.

Get the Right Fuel Injector the First Time

If your fuel injector is starting to fail, don’t wait for it to turn into a bigger problem.

👉 Verify your Engine Setup
👉 Replace Worn Injectors
👉 Restore Proper Combustion and Performance

Call our diesel experts at 844-304-7688 or browse parts online at Highway and Heavy Parts to get the right parts, faster.

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Common Case/New Holland Diesel Engine Problems

Case/New Holland diesel engines – powered largely by FPT Industrial platforms – are widely used across agriculture and heavy equipment.

You’ll see them in:

  • Combines
  • Tractors
  • Construction equipment
  • Industrial applications

Engines like the 8.7L and 12.9L platforms are built for demanding environments, but like any diesel engine under load, they have common failure points.

Understanding these issues early can help prevent downtime, repeat failures, and major engine damage.

Continue reading Common Case/New Holland Diesel Engine Problems
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Why Some Caterpillar C15 ACERT Inframe Rebuilds Fail Early (And How to Prevent It)

A Caterpillar C15 ACERT inframe rebuild should restore engine performance – not lead to another failure 50,000 miles later.

But that’s exactly what happens when critical measurements, tolerances, and supporting components are overlooked during the rebuild process.

Most early failures aren’t caused by the rebuild kit itself – they’re caused by what wasn’t checked before installation.

Continue reading Why Some Caterpillar C15 ACERT Inframe Rebuilds Fail Early (And How to Prevent It)
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Why Does My Diesel Engine Sound Like a Tractor?

A diesel engine is naturally louder than a gas engine. Some clatter, ticking, and combustion noise can be normal.

But if your diesel engine suddenly starts sounding louder, rougher, or more like an old tractor, that change matters.

A “tractor-like” diesel sound usually points to one of three things:

  1. Combustion noise
  2. Mechanical noise
  3. Exhaust or accessory noise

The important question is not just what the sound is.

It is whether the sound is new, getting louder, or paired with symptoms like low power, smoke, hard starting, or oil pressure concerns.

Continue reading Why Does My Diesel Engine Sound Like a Tractor?
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Perkins Engine Rebuild: Why the Crankshaft Won’t Turn After Assembly

You finish a Perkins engine rebuild, go to rotate the crankshaft. And it won’t move.

Or worse, it turns slightly and then binds.

This is one of the most frustrating problems after a rebuild, and it almost always comes down to clearance, alignment, or assembly issues.

If a crankshaft won’t turn freely after assembly, something is wrong. There is no “break-in” that will fix it.

Quick Answer: Why the Crankshaft Won’t Turn

  • Incorrect bearing clearances
  • Improper crankshaft machining
  • Main cap or rod cap misalignment
  • Thrust bearing installation issues
  • Debris or contamination during assembly
  • Incorrect torque sequence or values

Every one of these directly affects how the crankshaft rotates inside the block.

What “Normal” Should Feel Like

Quick takeaway: A properly assembled crankshaft should rotate smoothly with consistent resistance.

With:

  • Bearings installed
  • Caps torqued to spec
  • No pistons installed

You should be able to rotate the crankshaft by hand using a breaker bar. If you feel:

  • Tight spots
  • Binding
  • Uneven resistance

That indicates a mechanical issue: not normal assembly friction.

1. Incorrect Bearing Clearance (Most Common Cause)

Quick takeaway: Too little clearance will lock the crankshaft.

Diesel engines like Perkins rely on precise oil clearance between:

  • Crankshaft journals
  • Main and rod bearings

Typical oil clearance ranges for many Perkins engines:

  • ~0.0015″ to 0.0030″

If clearance is too tight:

  • Oil film cannot form
  • Metal-to-metal contact increases
  • Crankshaft binds or locks

This often happens when:

  • Bearings are mismatched
  • Journals are machined incorrectly
  • Clearances are not verified with plastigage or micrometers

2. Improper Crankshaft Machining

Crankshaft machining must be exact.

Common issues include:

  • Incorrect journal sizing
  • Out-of-round journals
  • Improper surface finish
  • Incorrect fillet radius after grinding

The fillet radius (the transition between journal and crank web) is critical.

If it is not properly finished:

  • Stress concentration increases
  • Bearing fit can be affected
  • Rotation can become restricted

In heavy-duty diesel applications, crankshafts are often:

  • Precision-ground
  • Sometimes shot-peened for durability

Crankshaft condition is just as important as machining accuracy. Learn more about what causes crankshaft damage in our guide on the four main causes of a bent diesel crankshaft: Bent Diesel Crankshaft Guide

3. Main Bearing Cap Misalignment

Quick takeaway: Main caps must be installed in the correct position and orientation.

Each main cap is:

  • Line-bored with the block
  • Matched to a specific position

If caps are:

  • Installed in the wrong location
  • Installed backwards
  • Torqued unevenly

This can:

  • Distort the crank bore
  • Pinch the crankshaft
  • Cause binding

Even slight misalignment can prevent rotation.

4. Thrust Bearing Installation Issues

The thrust bearing controls:

  • Crankshaft end play (forward/backward movement)

If installed incorrectly:

  • The crankshaft can bind when torqued

Common mistakes:

  • Thrust bearing installed backwards
  • Improper seating
  • End play not checked

Typical end play must be within spec—too tight and the crankshaft will not rotate freely.

5. Debris or Contamination During Assembly

Quick takeaway: Even small debris can lock a crankshaft.

After machining:

  • Metal shavings can remain in oil passages
  • Dirt or lint can contaminate surfaces

If debris gets between:

  • Bearing and journal
  • Bearing and cap

It can:

  • Reduce clearance
  • Create high spots
  • Cause immediate binding

This is why thorough cleaning after machining is critical.

6. Incorrect Torque Sequence or Values

Main caps and rod caps must be:

  • Torqued in sequence
  • Torqued to specification

If not:

  • The crankshaft bore can distort
  • Bearings can be unevenly loaded

This creates:

  • Tight spots during rotation
  • Inconsistent resistance

7. Rear Main Seal and Housing Issues (Perkins-Specific)

Some Perkins engines, such as the 4.108, use:

  • Rope-style rear main seals
  • Two-piece seal housings

If installed incorrectly:

  • The seal can drag on the crankshaft
  • Housing misalignment can create resistance

Common issues:

  • Seal trimmed incorrectly
  • Seal packed too tightly
  • Housing sealed improperly

This can make the crankshaft feel tight even if bearings are correct.

8. Connecting Rod Installation Problems

Once pistons and rods are installed, additional issues can appear:

  • Rod caps installed incorrectly
  • Bearing shells misaligned
  • Rods not properly sized

This can:

  • Add resistance
  • Cause binding at specific rotation points

How to Diagnose a Crankshaft That Won’t Turn

Quick takeaway: Isolate the problem step-by-step.

1. Remove Pistons and Rods

  • Check crank rotation with only main bearings installed

2. Check Each Main Cap Individually

  • Torque one cap at a time
  • Rotate crank after each step

3. Measure Bearing Clearance

  • Use plastigage or micrometers
  • Verify against spec

4. Check Crankshaft End Play

  • Verify thrust bearing installation
  • Measure with dial indicator

5. Inspect for Debris

  • Clean all surfaces thoroughly
  • Check oil passages

This Is a Precision Problem

We see this often:

The parts are new, but the system isn’t correct.

A crankshaft that won’t turn is not a defective part issue.
It’s almost always:

  • Machining
  • Measurement
  • Or assembly accuracy

Diesel engines require tight tolerances. Small errors create big problems.

Final Thoughts

If your Perkins engine crankshaft won’t turn after a rebuild, stop immediately.

Do not force it.

Binding is a sign that:

  • Clearances are incorrect
  • Components are misaligned
  • Or something was assembled improperly

Fixing the issue now prevents:

  • Bearing failure
  • Crankshaft damage
  • Complete engine failure

Browse our Perkins engine rebuild kits HERE

Or call 844-304-7688 to speak with a diesel expert.

From diagnosis through delivery, we’re Highway and Heavy Parts.

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Diesel Injector Symptoms: How To Tell If Your EUI Injectors Are Failing

If you’re noticing common diesel injector symptoms like rough idle, smoke, or loss of power, there’s a good chance your fuel system is the problem.

And if you’re running an engine with Electronic Unit Injectors (EUIs), the symptoms can show up fast – and get expensive even faster.

Because with EUIs, you’re not just dealing with fuel delivery.

You’re dealing with timing, pressure, and combustion all at once.

If one injector starts to fail, it doesn’t stay isolated.

Continue reading Diesel Injector Symptoms: How To Tell If Your EUI Injectors Are Failing
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When to Replace Fuel Injectors in a Caterpillar C15 Acert

Is your fuel efficiency down? Has the performance of your CAT C15 ACERT dropped?

Continue reading When to Replace Fuel Injectors in a Caterpillar C15 Acert
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VGT Turbo Problems and Symptoms: How Variable Geometry Failures Affect Boost, Heat, and Engine Performance

A Variable Geometry Turbocharger (VGT) does more than create boost.

It actively controls airflow, exhaust energy, and turbo speed across different engine conditions.

When a VGT system starts to fail, the issue is not just loss of power – it affects:

  • Boost Pressure Control
  • Exhaust Gas Temperature (EGT)
  • Air-Fuel Ratio
  • Emissions System Performance

Understanding how a VGT works – and how it fails – is key to diagnosing problems correctly.

Continue reading VGT Turbo Problems and Symptoms: How Variable Geometry Failures Affect Boost, Heat, and Engine Performance
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Why Diesel VGT Turbo Vanes Stick (And How to Tell If It’s the Turbo or the Actuator)

Variable Geometry Turbochargers (VGTs) are designed to adjust airflow dynamically—but when they fail, one issue shows up more than any other:

Sticking vanes. If the vanes can’t move, the turbo can’t control boost properly.

And that leads to:

  • Low power
  • Overboost or underboost
  • High exhaust temperatures
  • Fault codes

The challenge is this:

Not every VGT problem is actually a bad turbo.

Continue reading Why Diesel VGT Turbo Vanes Stick (And How to Tell If It’s the Turbo or the Actuator)
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Engine Belt Noise and Its Causes: How to Diagnose Squealing, Chirping, and More

If you’re hearing a squeal, chirp, or grinding noise coming from the front of your diesel engine, there’s a good chance the belts – or the components they drive – are involved.

But not all belt noise is actually caused by the belt itself.

The challenge is figuring out:

  • Or something deeper in the system
  • Whether it’s the belt
  • The tension
Continue reading Engine Belt Noise and Its Causes: How to Diagnose Squealing, Chirping, and More
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Diagnosing a Bad Cummins ISX Crankshaft: Symptoms and Replacement

The crankshaft is essentially the backbone of your truck’s engine. It keeps the engine moving and is vital to the overall health of your rig. When this critical component begins to fail in a Cummins ISX, it can quickly lead to severe mechanical damage and costly downtime. Recognizing the early warning signs of a worn or damaged crankshaft is essential to minimizing negative impacts to your revenue and keeping your truck out of the service bay.

Continue reading Diagnosing a Bad Cummins ISX Crankshaft: Symptoms and Replacement
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Detroit Diesel Series 60 Fuel Injectors (Remanufactured): How They Work, When They Fail, and Why Replacement Matters

On a Detroit Diesel Series 60, fuel injectors are directly tied to how the engine builds power.

Unlike older mechanical systems, the Series 60 uses electronic unit injectors (EUI) – meaning fuel delivery is controlled by both mechanical motion and electronic timing.

When everything is working correctly, the result is:

  • Precise Fuel Delivery
  • Efficient Combustion
  • Consistent Performance Under Load

When injectors start to fail, that precision is lost – and engine performance follows.

Continue reading Detroit Diesel Series 60 Fuel Injectors (Remanufactured): How They Work, When They Fail, and Why Replacement Matters
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Cummins N14 Fuel Injectors: How They Fail, What It Affects, and When to Replace Them

On a Cummins N14, fuel injectors are one of the most critical components controlling engine performance.

They don’t just deliver fuel – they control timing, atomization, and combustion efficiency.

And when they start to fail, the issue doesn’t stay isolated to one cylinder. It begins to affect engine balance, temperature, and long-term durability.

Continue reading Cummins N14 Fuel Injectors: How They Fail, What It Affects, and When to Replace Them
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Problems with EGR Systems in Diesel Engines

EGR systems are a standard part of modern diesel engines – but they are also one of the most common sources of frustration.

These systems are designed to reduce emissions and meet EPA regulations. However, they also introduce additional components that operate under high heat, pressure, and contamination.

Over time, this combination can lead to performance issues, costly repairs, and system failures.

Continue reading Problems with EGR Systems in Diesel Engines
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Why One Diesel Cylinder Runs Hotter Than the Others (And What It Means)

If one cylinder in your diesel engine is running hotter than the others, it’s not random.

It’s a sign of imbalance. In a diesel engine, imbalance means:

  • Uneven combustion
  • Uneven load distribution
  • Increased stress in one area

The important part is understanding why that one cylinder is different.

Continue reading Why One Diesel Cylinder Runs Hotter Than the Others (And What It Means)
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Diesel Engine Common Rail Injectors: Potential Failures & Causes

You’ve just been told that you need to replace your diesel engine fuel injectors, but what exactly caused the failure that led to this point?

Continue reading Diesel Engine Common Rail Injectors: Potential Failures & Causes
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Problems You Might Have with Your CAT C15 ACERT Diesel Engine Oil Pump

Lubrication is key to keeping your engine functioning properly. If your diesel engine isn’t properly lubricated, components could begin to wear more quickly and even seize up, costing you more money. The oil pump is critical to keeping your engine lubricated.

Continue reading Problems You Might Have with Your CAT C15 ACERT Diesel Engine Oil Pump
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What Problems Indicate Head Gasket Failure on C15 ACERT Diesel Engines?

We all know that the head gasket is important. It’s what creates the seal between the engine block and cylinder head to allow for combustion to happen. Without it, your diesel engine won’t run properly. 

Continue reading What Problems Indicate Head Gasket Failure on C15 ACERT Diesel Engines?
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When Should You Replace Your CAT C15 ACERT Diesel Engine Turbo?

As you probably know, one of the main differences between the Caterpillar C15 diesel engine and the C15 ACERT is the fact that the ACERT is designed with two turbochargers. That makes this component even more vital to the overall function and health of your diesel engine. 

Continue reading When Should You Replace Your CAT C15 ACERT Diesel Engine Turbo?
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Cylinder Head Problems on a Caterpillar C15 ACERT

Caterpillar C15 ACERT. You’ve probably heard of it. It’s a very popular engine, and we get a lot of questions on it from our customers.

Continue reading Cylinder Head Problems on a Caterpillar C15 ACERT
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When Do You Need New Fuel Injectors for Your Cat C15 ACERT Diesel Engine?

Has the performance of your CAT C15 ACERT taken a dive? Are you going through a lot more fuel than you used to? 

Continue reading When Do You Need New Fuel Injectors for Your Cat C15 ACERT Diesel Engine?
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Why Your Diesel Loses Power When Hot (But Runs Fine Cold)

If your diesel loses power when hot but runs strong when it’s cold, you’re not imagining it.

This is a common issue and one that gets misdiagnosed all the time.

👉 The key isn’t just what’s failing
👉 It’s why it only shows up when the engine gets hot

Continue reading Why Your Diesel Loses Power When Hot (But Runs Fine Cold)
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Why is My Diesel Engine EGR Valve Failing?

Do you know why you need your EGR valve? It’s an important component of your EGR system that takes a ton of abuse because of its environment, and it’s gotten a bad reputation over the years. People often choose to delete it because of the problems it can cause your diesel engine and VGT turbo. But, did you know that this can end up costing you more money in the long run?

Continue reading Why is My Diesel Engine EGR Valve Failing?
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An In-Depth Look at Diesel Engine Common Rail Fuel Injector Problems

If you’re experiencing problems with your common rail fuel injectors, you’ve probably noticed a difference in the way your diesel engine performs. And you’re probably eager to get the issue taken care of. 

Continue reading An In-Depth Look at Diesel Engine Common Rail Fuel Injector Problems
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Caterpillar C15 ACERT Diesel Engine Camshaft Problems

Is the camshaft in your CAT C15 ACERT diesel engine performing correctly? It’s essential that this component operates properly for your engine to function as it should. Each part of the camshaft must perform their functions at precise timing in relation to the motion of the piston. If they don’t, it could spell disaster for your diesel engine. 

Continue reading Caterpillar C15 ACERT Diesel Engine Camshaft Problems
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Problems That Require Cylinder Head Components for the CAT C15 ACERT Diesel Engine

You may not realize it, but there are a lot of components that make up the cylinder head of your C15 ACERT. If you have a failure in that part of your engine, you might be inclined to blame it on your cylinder head, but it’s possible that one of these other components could break. This would lead to problems with similar symptoms to that of a failing cylinder head.

Continue reading Problems That Require Cylinder Head Components for the CAT C15 ACERT Diesel Engine
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Problems with CAT C15 Diesel Engine Oil Pumps

Your oil pump. It’s probably not a part you’ve thought about a lot, but it serves an important role in your diesel engine.

Continue reading Problems with CAT C15 Diesel Engine Oil Pumps
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Why Oil Starvation Destroys Diesel Turbochargers

A turbocharger failure can look like a bad part.

Loss of power. Smoke. Noise. Oil leaking. Shaft play.

But in many heavy-duty diesel engines, the turbocharger is not the real starting point of the failure. The damage often begins somewhere else in the lubrication system.

The number one issue that destroys turbochargers is oil starvation. When a turbo does not receive a steady supply of clean, pressurized oil, internal damage can happen fast: sometimes within seconds under load.

Continue reading Why Oil Starvation Destroys Diesel Turbochargers
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Camshaft Failure Analysis: What Causes Excessive Lobe Wear (C15 Focus Included)

We all know how important camshafts are to engine performance – and when they fail, the damage can go far beyond the camshaft itself.

Whether you’re running a general diesel platform or a Caterpillar C15 diesel engine, one of the most common issues is camshaft lobe wear and pitting.

👉 And once it starts, it does not slow down – it accelerates.

Continue reading Camshaft Failure Analysis: What Causes Excessive Lobe Wear (C15 Focus Included)
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Diesel Fuel Contamination Problems: What’s Lurking in Your Fuel

Diesel fuel contamination problems are more common than most people realize.

Even when it meets specification at delivery, contamination can develop during storage, transport, or in your own fuel system. Over time, these contaminants affect fuel lubricity, combustion quality, and component life.

The most damaging contaminants are not always visible, but they leave very real mechanical consequences.

Continue reading Diesel Fuel Contamination Problems: What’s Lurking in Your Fuel
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CAT C15 ACERT Problems that Require a Diesel Engine Rebuild Kit

Did you know that performing regular maintenance can go a long way in keeping your diesel engine operating at its peak?

Continue reading CAT C15 ACERT Problems that Require a Diesel Engine Rebuild Kit
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Cummins ISX 870 Inframe Rebuild Problems: Why Engines Fail After a Rebuild

An inframe rebuild on a Cummins ISX 870 or ISX 871 is supposed to bring your engine back to life.

But for a lot of operators, that’s not what happens.

Instead, they run into problems almost immediately:

  • Oil Consumption
  • Blow-By
  • Low Power
  • Poor Fuel Economy

The issue usually isn’t the rebuild itself.

It’s what happens during – and right after – the rebuild.

Continue reading Cummins ISX 870 Inframe Rebuild Problems: Why Engines Fail After a Rebuild
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Caterpillar C15 ACERT Inframe Rebuild Kit: Why Twin Turbo Heat and Cylinder Pressure Drive Rebuild Failures

Caterpillar C15 ACERT engines don’t fail the same way older single-turbo engines do.

They operate under higher cylinder pressures, increased exhaust temperatures, and more complex airflow management due to the ACERT twin turbo system.

When these engines reach rebuild time, the failure is usually tied to one thing:

Heat and pressure overwhelming the cylinder assembly.

This is what drives liner wear, ring failure, and ultimately the need for an inframe rebuild.

Continue reading Caterpillar C15 ACERT Inframe Rebuild Kit: Why Twin Turbo Heat and Cylinder Pressure Drive Rebuild Failures
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Cummins ISB 6.7L Fuel Injectors: What Actually Fails Inside a Common Rail Injector

Fuel injectors in a Cummins ISB 6.7L common rail system don’t just deliver fuel.

They control timing, pressure, atomization, and combustion efficiency – all within milliseconds.

When an injector begins to fail, it’s not always obvious at first.

But internally, the failure has already started.

Continue reading Cummins ISB 6.7L Fuel Injectors: What Actually Fails Inside a Common Rail Injector
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International/Navistar DT466E Inframe Rebuild Kit: Wet Sleeve Wear, HEUI System Impact, and What to Verify Before Installation

The International/Navistar DT466E is known for its durability – but like all wet sleeve diesel engines, its longevity depends on cooling system condition, liner integrity, and fuel system performance.

When these engines start showing signs like blow-by, coolant loss, or hard starting, the issue is rarely isolated.

It’s typically the result of cylinder wear, liner sealing issues, or HEUI system inefficiencies affecting combustion.

If you’re planning an inframe rebuild, understanding these failure points is critical to avoiding repeat repairs.

Continue reading International/Navistar DT466E Inframe Rebuild Kit: Wet Sleeve Wear, HEUI System Impact, and What to Verify Before Installation
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Caterpillar C13 Inframe Rebuild Kit: Liner Seat Wear, Ring Seal Failure, and Combustion Efficiency

Caterpillar C13 engines are designed to handle heavy loads – but when internal wear sets in, performance loss isn’t random.

It’s the result of changes in cylinder geometry, sealing efficiency, and combustion pressure control.

If you’re considering an inframe rebuild, the key isn’t just replacing parts – it’s understanding what failed, why it failed, and what must be corrected during installation.

Continue reading Caterpillar C13 Inframe Rebuild Kit: Liner Seat Wear, Ring Seal Failure, and Combustion Efficiency
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Case IH Sprayer Pump Pressure Issues (Common Causes and How to Diagnose Them)

If you’re running a Case IH sprayer and dealing with pressure problems, you’re not alone.

Loss of pressure, inconsistent spray patterns, or pressure that won’t hold under load are some of the most common issues operators report – especially in models like the 4440 and 3340.

These problems are rarely isolated.

👉 Pump pressure issues are usually a symptom of a larger system problem.

Understanding where to look first can save time, prevent part swapping, and keep your equipment running during critical windows.

Continue reading Case IH Sprayer Pump Pressure Issues (Common Causes and How to Diagnose Them)
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Diesel Engine Blow-By: How Much Is Normal and When Should You Be Concerned?

If you’re seeing vapor coming from the breather or crankcase vent, you’re probably asking:

Is this normal or is my engine going bad?

That’s where a lot of confusion comes in.

Some blow-by is completely normal. But excessive blow-by can point to internal wear, poor sealing, or a bigger issue building over time.

The key is knowing the difference.

Continue reading Diesel Engine Blow-By: How Much Is Normal and When Should You Be Concerned?
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Cummins N14 Cylinder Head: Failure Points, Internal Stress, and What Happens When It Starts to Go

The Cummins N14 is built to handle heat and load – but the cylinder head is where those forces concentrate the most.

Over time, repeated thermal cycling, combustion pressure, and coolant flow stress begin to break things down at a microscopic level.

And when that happens, the issue usually doesn’t show up as “a bad head.”

It shows up as:

  • Coolant Loss
  • Overheating
  • Combustion Imbalance

By the time it’s obvious, the damage is already progressing.

Continue reading Cummins N14 Cylinder Head: Failure Points, Internal Stress, and What Happens When It Starts to Go
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Caterpillar C15 Fuel Injector Problems: Why Flow-Matched Injectors Matter More Than You Think

When a Caterpillar C15 starts showing signs of poor performance, fuel injectors are usually one of the first places technicians look.

But here’s where a lot of repairs go wrong:

The issue isn’t always a “bad injector.”
It’s often injector imbalance across the engine.

That’s where flow-matched injectors come into play. If you’re working on C15 engines in trucks, fleets, or heavy equipment, understanding this difference can prevent repeat failures and unnecessary downtime.

Continue reading Caterpillar C15 Fuel Injector Problems: Why Flow-Matched Injectors Matter More Than You Think
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Diesel Fuel Injector Failure Explained: Internal Leakage, Timing Loss, and Combustion Imbalance

Diesel fuel injectors do more than deliver fuel.

They control injection timing, atomization, pressure, and combustion efficiency.

When an injector begins to fail, the issue is rarely just “bad fuel delivery.”

It is usually a breakdown in one of three critical areas:

  • Internal Sealing
  • Injection Pressure Control
  • Spray Pattern Formation

Understanding these failure modes is the key to diagnosing problems correctly – and avoiding repeat failures.

Continue reading Diesel Fuel Injector Failure Explained: Internal Leakage, Timing Loss, and Combustion Imbalance
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Caterpillar C15, 3406E Turbocharger (177148): Boost, Failure, and What Happens When It Goes Bad

On a Caterpillar C15 or 3406E, the turbocharger isn’t just about power – it’s about air control, combustion efficiency, and engine balance.

When the turbo is working correctly, you get:

  • Proper Air-to-Fuel Ratio
  • Clean Combustion
  • Consistent Power Under Load

When it starts to fail, everything changes – and it usually shows up under load first.

Continue reading Caterpillar C15, 3406E Turbocharger (177148): Boost, Failure, and What Happens When It Goes Bad
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Caterpillar C15 ACERT Fuel Injector (10R1273): Symptoms, Failure Causes, and Replacement Guide

If your Caterpillar C15 ACERT is running rough, smoking more than usual, or losing power under load, there’s a good chance the issue is in the fuel system.

More specifically – the fuel injectors.

And when an injector like the 10R1273 starts to fail, it doesn’t just affect performance. It can impact combustion, fuel economy, and long-term engine health.

Continue reading Caterpillar C15 ACERT Fuel Injector (10R1273): Symptoms, Failure Causes, and Replacement Guide
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Caterpillar 3406E Engine Rebuild Kit: What Actually Fails and What You Need to Fix It Right

The Caterpillar 3406E is known for durability – but when it starts to go, it usually doesn’t fail all at once.

It starts small.

A little blow-by.
A little oil consumption.
Maybe a slight drop in power under load.

Then it builds.

And before long, you’re not looking at a repair anymore – you’re looking at a full engine rebuild.

Continue reading Caterpillar 3406E Engine Rebuild Kit: What Actually Fails and What You Need to Fix It Right
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Cummins ISX, QSX Cylinder Head: Symptoms, Failure Causes, and Replacement Guide

If your Cummins ISX or QSX is overheating, losing coolant, or showing signs of combustion issues, the problem may be deeper than a gasket or sensor.

It could be your cylinder head.

And when a cylinder head starts to fail, it doesn’t take long before it affects the entire engine.

Continue reading Cummins ISX, QSX Cylinder Head: Symptoms, Failure Causes, and Replacement Guide
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Detroit Diesel Series 60 Inframe Rebuild Kit: Liner Height, Bearing Wear, and What Actually Fails

Detroit Diesel Series 60 engines are known for durability – but when they reach high mileage, failure doesn’t happen all at once.

It happens in stages.

Most rebuild decisions start with symptoms like oil consumption, blow-by, or low oil pressure—but the real question is:

What’s actually worn out inside the engine – and what needs to be replaced to fix it correctly?

This guide breaks down the technical failure points and measurements that determine whether your Series 60 rebuild lasts – or comes back.

Continue reading Detroit Diesel Series 60 Inframe Rebuild Kit: Liner Height, Bearing Wear, and What Actually Fails
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Diesel Engine Noise During Clutch Engagement: Diagnosing Drag, Slip, and Hydraulic Failure

If you’re hearing noise when engaging the clutch, don’t ignore it.

What might seem like a minor issue – grinding, chatter, or a harsh engagement – can point to mechanical or hydraulic problems that will only get worse over time.

On heavy-duty diesel applications, clutch engagement issues typically fall into three categories:

  • Clutch Drag (Not Fully Disengaging)
  • Clutch Slip (Not Fully Engaging)
  • Hydraulic System Failure Or Imbalance

Understanding the difference is critical – because each one leads to very different failure paths.

Continue reading Diesel Engine Noise During Clutch Engagement: Diagnosing Drag, Slip, and Hydraulic Failure
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Caterpillar C15, 3406E Camshaft: Symptoms, Failure Causes, and Replacement Guide

If your Caterpillar C15 or 3406E isn’t running like it used to – losing power, misfiring, or making unusual noise – the problem might not be what you think.

It could be your camshaft.

And if that’s the case, waiting too long can turn a manageable repair into a full engine rebuild.

Continue reading Caterpillar C15, 3406E Camshaft: Symptoms, Failure Causes, and Replacement Guide
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Caterpillar 3406E Camshaft: Symptoms, Failure Causes, and Replacement Guide

If your Caterpillar 3406E is losing power, popping through the intake, or backfiring through the exhaust, the problem may not be fuel-related at all. In many cases, those symptoms point back to camshaft or valve train wear. When those components start to fail, performance can drop quickly, and if the issue is ignored, it can lead to more extensive engine damage and a much more expensive repair.

This article breaks down what the camshaft does, common signs of failure, why proper installation matters, and what to keep in mind when replacing a 3406E camshaft. If you are already looking for replacement parts, you can start by reviewing our Caterpillar 3406E Camshaft here.

Continue reading Caterpillar 3406E Camshaft: Symptoms, Failure Causes, and Replacement Guide
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Caterpillar C12 Camshaft Problems, Symptoms, and Replacement

If your Caterpillar C12 is losing power, running rough, or showing signs of valve train issues, the camshaft may be part of the problem. A worn camshaft can affect valve timing, engine efficiency, fuel economy, and overall performance. Left too long, what starts as a drivability issue can turn into a much larger repair.

Because the camshaft plays such a major role in how the engine breathes and performs, wear in this area should never be ignored. If you are already narrowing down the repair, our Caterpillar C12 Camshaft is a good place to start, and you can also browse more Caterpillar Engine Parts if the repair involves other related components.

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Cummins ISL G Cylinder Head Failures: Why Valve Seats Drop and How to Prevent It

The Cummins ISL G natural gas engine is built for a different type of combustion.

And that difference is exactly why the cylinder head fails the way it does.

Unlike diesel engines, ISL G failures are not typically caused by pressure.

They are caused by heat, material fatigue, and valve seat wear.

Continue reading Cummins ISL G Cylinder Head Failures: Why Valve Seats Drop and How to Prevent It
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Cummins ISX In-Frame Rebuild Failure: Why Your New Liners Aren’t Sealing (And How to Fix It)

You finished the in-frame. New liners, pistons, rings – everything looks right.

But now you’re seeing:

  • Blow-By
  • Oil Consumption
  • Low Compression
  • Or Worse… It’s Smoking Under Load

This isn’t uncommon on Cummins ISX engines – and it usually comes down to one issue:

Improper liner protrusion and ring seating during install.

If you don’t get this right, your rebuild won’t last – no matter how good your parts are.

Continue reading Cummins ISX In-Frame Rebuild Failure: Why Your New Liners Aren’t Sealing (And How to Fix It)
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Diesel Engine Ticking vs Knocking: How to Diagnose Valve Train Noise Before It Causes Damage

Not all engine noise is the same.

A ticking sound and a knocking sound may seem similar, but they point to very different issues inside your diesel engine.

In many cases, both originate in the valve train system – and both can escalate into major engine damage if ignored.

Continue reading Diesel Engine Ticking vs Knocking: How to Diagnose Valve Train Noise Before It Causes Damage
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How to Diagnose Diesel Engine Belt Noise: Identifying Pulley, Tensioner, and Accessory Failures

Belt noise on a diesel engine is not just an annoyance.

It is often an early warning sign of misalignment, bearing failure, or improper belt tension.

Ignoring it can lead to:

  • Accessory Failure
  • Loss Of Charging System
  • Cooling System Issues
  • Unexpected Downtime

Proper diagnosis requires understanding how the belt system operates under load.

Continue reading How to Diagnose Diesel Engine Belt Noise: Identifying Pulley, Tensioner, and Accessory Failures
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Caterpillar C10 and C12 Cylinder Head Failure: Cracking, Valve Seat Wear, and When Replacement Is Required

The cylinder head on a Caterpillar C10 or C12 isn’t just a casting – it’s where combustion, airflow, and cooling all come together.

And when it fails, it usually doesn’t fail quietly.

Cracked heads, worn valve seats, and injector cup issues are some of the most common – and most expensive – problems we see on these engines. If you’re already chasing coolant loss, misfires, or compression issues, there’s a good chance the cylinder head is involved.

Continue reading Caterpillar C10 and C12 Cylinder Head Failure: Cracking, Valve Seat Wear, and When Replacement Is Required
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Why Diesel Fuel Systems Are So Sensitive (And How Small Issues Turn Into Major Repairs)

If you’ve ever dealt with a diesel fuel system issue, you know how quickly things can escalate. What starts as a minor problem – like a slight misfire, rough idle, or extra smoke – can quickly turn into major engine damage if it’s not addressed early.

That’s what makes modern diesel fuel systems so challenging.

They’re not just sensitive – they’re precise to the point where even small disruptions can create serious problems. When something in the system changes – even slightly – it directly impacts combustion. If you’re already dealing with fuel system issues or looking to prevent them, you can explore our full range of diesel fuel system components designed for reliability and performance.

Continue reading Why Diesel Fuel Systems Are So Sensitive (And How Small Issues Turn Into Major Repairs)
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Detroit Diesel Series 60 Common Issues and Failures

Do you own a Detroit Diesel Series 60 engine? It probably runs well for the most part. All three versions of this electronically-controlled engine have a favorable reputation; despite being out of production for years, the Series 60 remains a popular choice for many truck drivers.

Continue reading Detroit Diesel Series 60 Common Issues and Failures
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Dirty Diesel Fuel Injectors: What’s Really Happening Inside (And Why Cleaning Isn’t Enough)

Dirty or clogged diesel fuel injectors are one of the most common – and most misunderstood – fuel system problems.

A lot of people think it’s just a restriction issue. Spray some cleaner, maybe swap a filter, and you’re good to go.

But in reality, injector contamination leads to precision failure inside the injector itself – and once that starts, performance drops fast.

Before you try a quick fix, it’s important to understand what’s actually happening inside your injectors.

Continue reading Dirty Diesel Fuel Injectors: What’s Really Happening Inside (And Why Cleaning Isn’t Enough)
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Detroit Diesel Series 60 Oil Pump Failure: Causes, Oil Pressure Loss, and When to Replace

The oil pump in your Detroit Diesel Series 60 isn’t just another component – it’s the heart of your lubrication system. When it starts to fail, the damage doesn’t stay isolated. It spreads fast.

Low oil pressure, bearing wear, and even full engine failure can all trace back to one root issue: inconsistent oil delivery.

If you’re working on a Series 60, understanding how the oil pump fails – and how to catch it early – can be the difference between a simple repair and a full rebuild.

Continue reading Detroit Diesel Series 60 Oil Pump Failure: Causes, Oil Pressure Loss, and When to Replace
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Diesel Engine Overheating: How to Diagnose the Problem

Diesel engine overheating is one of the most common – and most damaging – issues you can face.

What starts as a slight temperature increase can quickly turn into major engine damage if not diagnosed correctly.

If your diesel engine is overheating, identifying the root cause early is critical to preventing expensive repairs and downtime.

Continue reading Diesel Engine Overheating: How to Diagnose the Problem
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Cummins L10 Cam Follower Failure: How Cam Lever Rollers Control Valve Train Geometry

The cam follower in a Cummins L10 is a small component with a very large job.

It directly transfers motion from the camshaft to the valve train.

And when it fails, it doesn’t just affect performance – it can lead to catastrophic engine damage.

What the Cam Lever Follower Actually Does

In the Cummins L10 valve train, the camshaft does not directly actuate the valves.

Instead, motion is transferred through a cam follower (cam lever with roller).

This component:

  • Converts Rotational Camshaft Motion Into Linear Movement
  • Maintains Correct Valve Timing And Lift
  • Reduces Friction Through A Roller Contact Surface

The roller rides directly on the cam lobe, making this a high-load, high-contact stress interface.

Why Roller Followers Are Used Instead of Flat Tappets

The Cummins L10 uses a roller-style follower to reduce friction and wear.

Compared to flat tappets, roller followers:

  • Reduce Sliding Friction At The Cam Lobe Interface
  • Lower Heat Generation
  • Improve Camshaft Longevity
  • Maintain More Consistent Valve Timing Over Time

However, this design introduces a different failure risk — roller bearing failure.

Contact Stress and Load Distribution at the Cam Lobe

The cam-to-roller interface experiences extreme contact pressure.

This is a classic Hertzian contact stress scenario, where:

  • Load Is Concentrated Over A Small Contact Area
  • Surface Hardness And Lubrication Are Critical
  • Any Imperfection Leads To Accelerated Wear

Under normal conditions, a hydrodynamic oil film separates the surfaces.

But when lubrication is compromised, metal-to-metal contact occurs.

How Cam Followers Fail

Cam follower failures typically start small but escalate quickly.

Common failure modes include:

  • Roller Bearing Wear Or Seizure
  • Flat Spots On The Roller Surface
  • Spalling Or Pitting Of The Roller
  • Misalignment Of The Follower

Once the roller stops rotating:

  • Sliding Friction Replaces Rolling Contact
  • Heat Increases Rapidly
  • Cam Lobe Wear Accelerates

What Happens When the Roller Stops Turning

This is where failure becomes severe.

A seized roller creates:

  • Direct Sliding Contact Against The Cam Lobe
  • Rapid Material Removal From The Camshaft
  • Loss Of Proper Valve Lift Profile

This leads to:

  • Incorrect Valve Timing
  • Reduced Airflow And Combustion Efficiency
  • Increased Stress On Other Valve Train Components

Eventually, this can damage:

  • Camshaft Lobes
  • Pushrods
  • Rocker Arms

Lubrication: The Critical Failure Variable

The cam follower depends entirely on proper lubrication.

Oil must:

  • Reach The Roller Bearing
  • Maintain A Film Between Cam And Roller
  • Remove Heat From The Contact Area

Failure causes related to lubrication include:

  • Low Oil Pressure
  • Contaminated Oil (Debris Or Soot)
  • Oil Starvation During Startup

Without lubrication, failure accelerates rapidly.

Secondary Damage from Cam Follower Failure

A failing cam follower rarely fails alone.

It creates a chain reaction:

  • Camshaft Lobe Wear Alters Valve Timing
  • Metal Debris Circulates Through The Engine
  • Additional Components Experience Accelerated Wear

In severe cases, this can lead to:

  • Complete Valve Train Failure
  • Engine Tear-Down Requirements

Signs of a Failing Cam Follower

Early detection can prevent major damage.

Watch for:

  • Unusual Valve Train Noise (Ticking Or Knocking)
  • Loss Of Engine Performance
  • Metal Particles In Oil Analysis
  • Irregular Valve Operation

These symptoms often appear before catastrophic failure.

Why Inspection During Rebuild Is Critical

Cam followers should always be inspected during an overhaul.

Key checks include:

  • Roller Rotation Smoothness
  • Surface Condition Of The Roller
  • Bearing Integrity
  • Alignment And Wear Patterns

Reusing worn components increases the risk of immediate failure.

When to Replace Cam Followers

Replacement is recommended when:

  • Roller Wear Or Pitting Is Visible
  • Bearing Play Exists
  • The Roller Does Not Rotate Freely
  • Camshaft Wear Is Present

It is often best practice to replace followers when replacing the camshaft.

Shop Cummins L10 Cam Followers

If you’re rebuilding your engine or diagnosing valve train issues, cam followers should not be overlooked.

👉 Shop Cummins L10 Products

At Highway and Heavy Parts:

  • Verified Fitment Before Shipping
  • High-Quality Components Built For Heavy-Duty Applications
  • Fast Shipping (1–2 Days In Most Areas)
  • Expert Diesel Support
  • Parts And Labor Warranty

Small Component, Major Consequences

The cam follower may seem minor.

But it directly affects:

  • Valve Timing
  • Engine Efficiency
  • Component Longevity

Ignoring it can lead to major repairs.

Protect Your Valve Train System

Proper function depends on correct operation across all components.

👉 Maintain Proper Oil Quality And Pressure
👉 Inspect Valve Train Components During Service
👉 Replace Worn Components Before Failure Occurs

Call 844-304-7688 to speak with a diesel parts specialist
or visit highwayandheavyparts.com to find the right rebuild kit for your engine.

From diagnosis to delivery, Highway and Heavy Parts has your back.

Cummins L10 Cam Followers For Sale From Highway and Heavy Parts!

Continue reading Cummins L10 Cam Follower Failure: How Cam Lever Rollers Control Valve Train Geometry

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Diesel Engine Failure Diagnosis: Compression Issues

There are many possible causes of engine failure. You can see our earlier post on diagnosing engine failures, too.

Continue reading Diesel Engine Failure Diagnosis: Compression Issues
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Volvo D13 / Mack MP8 Turbo Overspeed Failure: What Causes It And Why Replacing The Turbo Isn’t Enough

Turbocharger failure on a Volvo D13 or Mack MP8 engine isn’t always caused by wear – it’s often the result of turbo overspeed conditions driven by VGT control issues, exhaust imbalance, or air system faults.

In many cases, the turbo fails because it was forced to operate outside of its design limits – not because the turbo itself was defective.

Understanding what causes turbo overspeed is critical to preventing repeat failures.

Continue reading Volvo D13 / Mack MP8 Turbo Overspeed Failure: What Causes It And Why Replacing The Turbo Isn’t Enough
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Cummins ISX Inframe Rebuild Failure: Why Your New Liners Aren’t Sealing (And How to Fix It)

You finished the inframe. New liners, pistons, rings – everything looks right.

But now you’re seeing:

  • Blow-By
  • Oil Consumption
  • Low Compression
  • Or Worse… It’s Smoking Under Load

This isn’t uncommon on Cummins ISX engines – and it usually comes down to one issue:

Improper liner protrusion and ring seating during install.

If you don’t get this right, your rebuild won’t last – no matter how good your parts are.

Continue reading Cummins ISX Inframe Rebuild Failure: Why Your New Liners Aren’t Sealing (And How to Fix It)
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DD15 Diesel Engine Pistons: How They Control Blow-By and What Causes Failure

Blow-by is not just a symptom.

It is a direct result of combustion pressure escaping past the piston assembly.

On a Detroit Diesel DD15, controlling blow-by comes down to one thing:

How well the piston, rings, and liner seal under load.

If that seal fails, everything else starts to follow.

Continue reading DD15 Diesel Engine Pistons: How They Control Blow-By and What Causes Failure
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Cummins ISX Crankshaft Failure: Signs, Causes, and What to Do Before It Costs You an Engine

When a Cummins ISX starts running rough, vibrating, or misfiring, most people don’t immediately think about the crankshaft.

That’s the problem.

Because by the time the crankshaft shows obvious symptoms, the damage is usually already happening inside the engine – and it doesn’t take long before it turns into a full rebuild.

If you’re dealing with vibration, low oil pressure, or unusual engine noise, this is one issue you don’t want to ignore.

Continue reading Cummins ISX Crankshaft Failure: Signs, Causes, and What to Do Before It Costs You an Engine
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Detroit Diesel Series 60 14L Turbocharger: Symptoms, Failure Causes, and When to Replace

The turbocharger on a Detroit Diesel Series 60 14L engine does more than add power.

It controls airflow, and airflow controls combustion.

When the turbo isn’t performing correctly, the entire engine starts to fall out of balance.

Continue reading Detroit Diesel Series 60 14L Turbocharger: Symptoms, Failure Causes, and When to Replace
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Caterpillar C15 and 3406E Oil Pump: Symptoms, Failure Causes, and When to Replace

Low oil pressure isn’t something you ignore on a diesel engine.

On a Caterpillar C15 or 3406E, it’s often a warning sign that something deeper is going wrong inside the engine.

And in many cases, the issue starts with the oil pump.

Continue reading Caterpillar C15 and 3406E Oil Pump: Symptoms, Failure Causes, and When to Replace
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What Happens When a Diesel Engine Sits Too Long? (Fuel, DEF, and Internal Damage Explained)

Diesel engines are built to run – not sit.

At Highway and Heavy Parts, we regularly work with engines that come out of storage with unexpected performance issues. In many cases, the root cause isn’t a failed part: it’s what happened while the engine wasn’t running.

Whether it’s a backup truck, seasonal equipment, or a unit waiting on work, extended downtime can quietly create problems that don’t show up until the engine is put back into service.

And in many cases, those problems get misdiagnosed.

From fuel degradation to DEF crystallization and internal wear, here’s exactly what happens when a diesel engine sits too long – and what to look for before putting it back to work.

Continue reading What Happens When a Diesel Engine Sits Too Long? (Fuel, DEF, and Internal Damage Explained)
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What Does It Cost to Replace a Diesel Fuel Injector in 2026?

If your diesel engine is running rough, smoking, or losing power, a failing fuel injector could be the cause.

One of the first questions most people ask is: How much does it cost to replace a diesel fuel injector?

The answer depends on your engine, injector type, and how far the issue has progressed. Some injector problems are caught early. Others turn into much larger repairs.

Let’s break down what actually impacts the cost – and what you can expect in 2026.

Continue reading What Does It Cost to Replace a Diesel Fuel Injector in 2026?
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10 Common Causes of Excessive Oil Consumption in Diesel Engines

Diesel engines are built for durability – but excessive oil consumption is one issue that can quickly turn into a costly repair.

If you’re constantly adding oil, noticing blue smoke, or seeing a drop in performance, there’s usually an underlying mechanical reason.

In this guide, we’ll break down the 10 most common causes of excessive oil consumption in diesel engines, what each one means, and what to check before it turns into a major failure.

Continue reading 10 Common Causes of Excessive Oil Consumption in Diesel Engines
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Cummins ISX Fuel Injector Problems: Symptoms, Causes, and Replacement Guide

If your Cummins ISX is hard starting, losing power, or producing excessive smoke, failing fuel injectors could be the cause.

Injector issues don’t usually show up all at once.

They start small, but if ignored, they can quickly turn into major engine problems.

Understanding the symptoms – and addressing them early – can save you time, money, and downtime.

Continue reading Cummins ISX Fuel Injector Problems: Symptoms, Causes, and Replacement Guide
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Caterpillar C15 and 3406E Oil Cooler: How It Works, Failure Symptoms, and Why It Matters

The oil cooler on a Caterpillar C15 or 3406E does more than regulate temperature.

It protects:

  • Oil Viscosity
  • Bearing Life
  • Internal Engine Clearances

If the oil cooler fails, it doesn’t just affect oil temperature.

It affects the entire engine.

Continue reading Caterpillar C15 and 3406E Oil Cooler: How It Works, Failure Symptoms, and Why It Matters
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7 Common Detroit Diesel Series 60 Problems

Do you have a Series 60 engine from Detroit? For the most part, it probably runs great for you. This electronically controlled engine has a favorable history, shared between all three versions, and despite having been out of production for years now, it remains a popular choice for many operators.

Continue reading 7 Common Detroit Diesel Series 60 Problems
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Diesel Turbocharger Sounds: What They Mean and When to Inspect

A diesel turbocharger is not silent.

A light whistle, whoosh, or spool sound under load can be completely normal. However, when the sound changes suddenly, gets louder, or comes with smoke, low power, or oil consumption, it can point to a problem in the turbocharger system.

The key is not just hearing the sound.

It is understanding what kind of sound it is, when it happens, and what else the engine is doing at the same time.

Turbocharger noise can come from the turbo itself, but it can also come from boost leaks, exhaust leaks, restricted air filters, fuel system problems, damaged exhaust components, or lubrication issues. Garrett specifically notes that noisy performance, low power, smoke, and oil consumption can come from underlying engine problems—not always the turbocharger itself.

Continue reading Diesel Turbocharger Sounds: What They Mean and When to Inspect
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Diesel Cylinder Head Cracking: 4 Causes, Symptoms & Prevention

Diesel cylinder head cracking is one of the most serious issues an engine can face – and one of the most expensive if it’s not caught early.

What makes it worse is that it often starts small.

A minor overheating event, a stress point in the casting, or an installation issue can eventually turn into coolant loss, compression problems, and complete engine failure.

Understanding what causes cylinder head cracking – and what to look for – can help prevent repeat failures and unnecessary downtime.

Continue reading Diesel Cylinder Head Cracking: 4 Causes, Symptoms & Prevention
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Caterpillar C15, C15 ACERT, and 3406E Cylinder Head: Failure Symptoms, Causes, and When to Replace

The cylinder head on a Caterpillar C15, C15 ACERT, or 3406E is one of the most critical components in the engine.

It controls:

  • Combustion Sealing
  • Airflow into the Cylinders
  • Exhaust Flow out of the Engine
  • Fuel Injector Operation

When the cylinder head starts to fail, it doesn’t stay contained. It affects the entire engine.

Continue reading Caterpillar C15, C15 ACERT, and 3406E Cylinder Head: Failure Symptoms, Causes, and When to Replace
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Why Correct Fuel Injector Trim Codes Still Result in Poor Engine Performance

You’ve replaced the injectors.
You’ve programmed the trim codes correctly.
Everything checks out – and the engine still runs rough.

This is more common than most people realize.

Fuel injector trim codes are designed to fine-tune fuel delivery, but they are not a fix-all. If the engine is still underperforming, the issue is almost always outside the trim code itself.

Continue reading Why Correct Fuel Injector Trim Codes Still Result in Poor Engine Performance
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Caterpillar C15 Head Gasket Problems: Failure Points, Diagnosis, and Replacement

Head gasket problems on the Caterpillar C15 are rarely random.

They are almost always tied to:

  • Heat
  • Clamping force
  • Or failure in related components like the spacer plate or cylinder head

If you’re seeing coolant, oil, or pressure issues – especially toward the left side or rear of the engine – you’re already looking in the right place.

Continue reading Caterpillar C15 Head Gasket Problems: Failure Points, Diagnosis, and Replacement
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Low Boost Diesel No Check Engine Light: Causes and Diagnosis

If you’re dealing with low boost diesel no check engine light, you’re not alone.

This is one of the most common complaints we hear.

It’s also one of the most misdiagnosed. And because there’s no fault code, it’s easy to assume:

  • The issue isn’t serious
  • It’s electrical
  • Or nothing is actually wrong

In reality, low boost with no warning light is usually a mechanical or system efficiency issue.

Continue reading Low Boost Diesel No Check Engine Light: Causes and Diagnosis
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Caterpillar C15 Fuel Injector Failures: Precise Diagnosis, Failure Modes, and Replacement Strategy

If a Caterpillar C15 starts to smoke, miss, haze at idle, or loses power under load, injectors are high on the list: but guessing is what gets engines hurt.

On many C15 variants (notably HEUI systems), injectors are hydraulically actuated by high-pressure engine oil. That means injector performance depends on two systems at once:

  • Fuel supply (clean, stable pressure)
  • Actuation oil (ICP/IAP pressure, clean oil, correct viscosity)

When either side is off, injector behavior changes.

What “Correct” Looks Like

With a healthy system:

  • Smooth idle, even exhaust note
  • Stable rail/actuation pressure under load
  • Balanced cylinder contribution
  • Minimal visible smoke once warm

Any deviation should be traced to a cylinder, then to a cause – not straight to parts replacement.

Primary C15 Injector Failure Modes (What Actually Fails)

1) Internal Leakage → Fuel Dilution (High Risk)

Mechanism

  • Worn check valve or sealing surfaces inside injector
  • Failed injector O-rings (upper/middle/lower) allowing cross-leakage

What happens

  • Fuel bypasses normal metering
  • Fuel can enter the cylinder uncontrollably or migrate past rings

Hard indicators

  • Engine oil level rising with no external leak
  • Oil smells like diesel
  • Reduced oil viscosity → bearing risk

Why it matters

  • Fuel-diluted oil cannot maintain hydrodynamic film
  • Main and rod bearings are at risk quickly

2) Solenoid / Electrical Control Failure

Mechanism

  • Coil failure, high resistance, intermittent connection
  • Damaged injector pigtail or harness

What happens

  • Injector fails to open/close precisely
  • Timing and duration errors

Hard indicators

  • Misfire at specific cylinder
  • Contribution test shows weak cylinder
  • Electrical codes may or may not set

Key point
Electrical faults can look identical to mechanical injector failure – verify before replacing.

3) Nozzle Wear, Erosion, or Coking

Mechanism

  • High-pressure fuel erodes or deforms nozzle holes
  • Carbon buildup (“coking”) distorts spray pattern

What happens

  • Poor atomization
  • Larger droplets → incomplete burn

Hard indicators

  • Black smoke under load (overfueling/poor burn)
  • Elevated EGT on affected cylinder
  • Soot accumulation increases

Result

  • Higher piston crown temperature
  • Long-term risk to valves and liners

4) Sticking Injector (Open or Closed Behavior)

Mechanism

  • Deposits or wear cause internal components to hang

What happens

  • Injector stuck open → overfueling
  • Injector stuck closed → dead cylinder

Hard indicators

  • White/gray smoke (raw fuel) or dead miss
  • Engine may clear up as it warms (thermal expansion)
  • Severe cases: cylinder washdown

5) Seal/O-Ring Failure (Fuel/Air Cross-Leak)

Mechanism

  • O-ring degradation from heat, age, or contamination

What happens

  • Air intrusion into fuel system
  • Fuel pressure instability
  • Cross-port leakage

Hard indicators

  • Hard start after sitting
  • Aerated fuel symptoms
  • Inconsistent performance

6) HEUI-Specific: Actuation Oil Problems Misdiagnosed as Injectors

Mechanism

  • Low ICP/IAP pressure
  • Aerated or contaminated oil
  • High-pressure oil leaks (o-rings, rail)

What happens

  • Injectors cannot achieve commanded fuel pressure
  • Poor response, misfires under load

Hard indicators

  • Low actuation pressure vs commanded
  • Multiple cylinders affected
  • Improves with RPM (sometimes)

Key point
This is often misdiagnosed as “bad injectors”.

Diagnostic Workflow (What Actually Works)

Do not start with parts. Start with isolation.

1) Cylinder Cut-Out / Contribution Test

  • Disable one cylinder at a time (via Cat ET or manual method)
  • Watch RPM drop or fuel correction

Result

  • Weak change → suspect that cylinder

2) Verify Fuel Supply Pressure

  • Check at filter base or test port
  • Ensure stable pressure during crank and load

Why
Low supply pressure affects all injectors and mimics failure.

3) Check Actuation Oil Pressure (HEUI)

  • Compare actual vs commanded ICP/IAP
  • Look for lag, drop, or instability

Why
No actuation pressure = no injector performance.

4) Valve Cover Inspection

Look for:

  • Fuel wash (clean, stripped oil areas)
  • Oil dilution signs

Fuel wash indicates:
→ injector leaking into that cylinder

5) Temperature Comparison (Advanced but Effective)

  • Use IR gun on exhaust manifold runners

Result

  • Cold cylinder → underfueling/misfire
  • Hot cylinder → overfueling/poor atomization

Replacement Strategy (What Actually Makes Sense)

Replace One Injector vs Set?

  • Single failure, low hours: targeted replacement is acceptable
  • High mileage / multiple symptoms: replace as a set

Reason:

  • Injector balance matters
  • Mixed wear levels create uneven combustion

Always Replace:

  • Injector O-ring kits
  • Any damaged cups (if applicable)
  • Verify harness/pigtails

After Replacement:

  • Prime fuel system
  • Verify pressures
  • Recheck contribution balance

What Causes Repeat Injector Failures

Injectors rarely fail in isolation.

Common root causes:

  • Contaminated fuel
  • Poor filtration maintenance
  • Low fuel pressure
  • Air intrusion
  • Oil system issues (HEUI engines)

If the root cause isn’t fixed:
→ new injectors will fail again

HHP Insight: Don’t Treat Injectors as the Root Problem

Most repeat failures come from:

  • Fuel system imbalance
  • Actuation pressure issues
  • Contamination

Injectors are often the symptom, not the cause.

Final Thoughts

C15 injector problems are not just about replacing parts.

They’re about:

  • Identifying the failing cylinder
  • Verifying fuel and oil systems
  • Understanding combustion behavior

That’s how you prevent:

  • Repeat failures
  • Engine damage
  • Unnecessary costs

Need Caterpillar C15 fuel injectors?

Shop here:
👉 Caterpillar C15 Fuel Injectors

Or call 844-304-7688 to speak with a diesel expert.

From diagnosis through delivery, we’re Highway and Heavy Parts.

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Why Intake Valve Seats Fall Out In Diesel Cylinder Heads After Overheating

A dropped valve seat in a diesel engine isn’t just a cylinder head issue – it’s a direct result of thermal stress, material expansion, and loss of interference fit.

This type of failure is most commonly seen after an overheating event, and once it happens, the damage is usually severe enough to require cylinder head replacement and, in many cases, piston repair.

Understanding why valve seats fail – and what leads up to it – is critical to preventing repeat engine damage.

Continue reading Why Intake Valve Seats Fall Out In Diesel Cylinder Heads After Overheating
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Bosch High Pressure Diesel Oil Pump: Signs of Failure and the Benefits of a Replacement

Is your Navistar/International DT466/I530 HEUI High Pressure Oil Pump showing signs of reduced power, decreased fuel economy, increased emissions, or rough running? We can help you recognize the signs of failure and inform you on all of the benefits of replacing your oil pump with a Genuine Bosch oil pump from HHP.

Continue reading Bosch High Pressure Diesel Oil Pump: Signs of Failure and the Benefits of a Replacement
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Why Your Caterpillar C15 ACERT Turbocharger Might Not Be the Real Problem

If you’re dealing with low power, smoke, or oil around the turbo on a Caterpillar C15 ACERT, it’s easy to assume the turbocharger has failed.

But that’s not always the case.

At Highway and Heavy Parts, we see this all the time – turbos get replaced, but the original problem is still there. That’s because many turbo “failures” are actually symptoms of fuel system issues, oil problems, or internal engine wear.

Before replacing your turbo, it’s critical to understand what’s really going on.

Continue reading Why Your Caterpillar C15 ACERT Turbocharger Might Not Be the Real Problem
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Caterpillar C15 Head Gasket Failure: Root Causes, Symptoms, And Proper Repair Process

A failed head gasket on a Caterpillar C15 isn’t just a sealing issue – it’s usually the result of improper clamping force, liner height variation, or thermal stress inside the engine.

Replacing the gasket without addressing the underlying cause often leads to repeat failure.

Understanding why the gasket failed is critical before installing a new cylinder head gasket set.

Continue reading Caterpillar C15 Head Gasket Failure: Root Causes, Symptoms, And Proper Repair Process
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Dinex Emission: The Solution to Diesel Pollution

Dinex Emission is a company that has been dedicated to helping diesel operators meet the high standards of the EPA for a very long time. Though the EPA’s goal is to reduce the emissions of dangerous gasses into the air, their restrictions can often make transporting goods, completing construction projects, and harvesting large crops more difficult. As an expert in the field of diesel emissions control, Dinex has long been the solution to this obstacle.

Continue reading Dinex Emission: The Solution to Diesel Pollution
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Common Diesel Engine Problems and Solutions

Diesel engines are workhorses, powering everything from trucks to heavy machinery. However, like any complex machinery, they can encounter problems. Let’s explore some of the most common issues and their solutions:

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How To Know If Your Fuel Pump Is Failing

Do you think you need a new high-pressure pump for your Detroit engine, but aren’t sure how to tell if it’s really time? Do you know what your options are?

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Symptoms of a Failing C15 ACERT Turbocharger

Your turbocharger is important to the overall health of your CAT C15 ACERT diesel engine. So, it’s important to replace it when something goes wrong.

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Failing Fuel Injectors In Cummins N14 Diesel Engines

Having properly operating fuel injectors is vital to the health of your diesel engine. If they’re not working at their best, then you might be experiencing a lot of other problems as well.

Continue reading Failing Fuel Injectors In Cummins N14 Diesel Engines
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Camshaft Problems with Caterpillar C15 ACERT Engines

Camshaft problems can spell major issues for your Caterpillar C15 ACERT. This component needs to be functioning at its best for optimal engine performance.

Continue reading Camshaft Problems with Caterpillar C15 ACERT Engines
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Head Gasket Failure In Your Caterpillar C15 Acert Engine

Your head gasket creates the seal between the engine block and the cylinder head, allowing for combustion. It’s vital to the overall performance of your engine, and without it, your engine couldn’t run properly.

Continue reading Head Gasket Failure In Your Caterpillar C15 Acert Engine
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Rocker Lever Issues In Your Overhead Cam Engine

If you have an overhead cam engine—a Detroit Diesel Series 60, a Cummins ISX, a Caterpillar 3406E or C15, for example—you might have some questions about rocker levers.

Continue reading Rocker Lever Issues In Your Overhead Cam Engine
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Piston Crown Failure Analysis

The internal combustion engine is a true marvel of modern engineering. Diesel engines are found in almost all heavy-duty machinery, trucks, construction equipment, etc. But what happens when they fail? We are going to dive deeper into piston crown failure, why it happens, and what can be done to possibly prevent future issues. If you find yourself with damaged pistons crowns, count on Highway and Heavy Parts to help get you back up and running with as little downtime as possible. Here are the most common causes of piston crown failure.

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Ultra Performance Cylinder Heads

At Highway and Heavy Parts, we’re dedicated to bringing you the best information about diesel engine parts around. We want you to feel confident as you shop for parts, grow your business, and successfully identify what you need for the job at hand.

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Problems with Caterpillar C15 Oil Pumps

Have you ever thought much about your oil pump?

Continue reading Problems with Caterpillar C15 Oil Pumps
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Caterpillar C15 ACERT Oil Pump Failure

Diesel engines are made up of thousands of moving parts, and keeping them lubricated comes down to having a correctly working oil pump. If the oil pump on your Cat C15 ACERT Diesel engine is not working properly, failure and damage is the only possible outcome.

Continue reading Caterpillar C15 ACERT Oil Pump Failure
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Experiencing Cylinder Head Problems On A Caterpillar C15 ACERT

The Caterpillar C15 ACERT diesel engine is no doubt one of the most popular heavy-duty machinery engines. Unfortunately, it has been documented as being a little problematic, to say the least, especially when it comes to their cylinder heads.

Continue reading Experiencing Cylinder Head Problems On A Caterpillar C15 ACERT
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Is Your Caterpillar C15 Turbo Working Right? Symptoms of Failure and Causes

Maybe you’ve noticed lower power or boost in your CAT C15. Or maybe the overall performance just isn’t where it should be.

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7 Common Caterpillar C15 Cylinder Head Problems

Caterpillar has been a renowned manufacturer of heavy-duty diesel engines since its inception nearly 100 years ago. The C15 has been an integral part of helping keep the Caterpillar name at the top of everyone’s list. Have a look at our Cat C15 engine spotlight here!

Continue reading 7 Common Caterpillar C15 Cylinder Head Problems
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Symptoms Your Mack Diesel Fuel System Is Failing

It’s vital that the fuel system on your diesel engine is functioning properly. So, when it comes time to replace some of the fuel system components on your Mack diesel engine, you want to make sure that you’re getting the best!

Continue reading Symptoms Your Mack Diesel Fuel System Is Failing
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Common Symptoms Your Diesel Fuel Pump Is Failing

When your engine is down, we know you want to get it back up and running as soon as possible. Highway & Heavy Parts has you covered! We’ve got the best quality parts at the best prices to get your engine performing like it should, saving you time and money!

Continue reading Common Symptoms Your Diesel Fuel Pump Is Failing
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Why Did My Diesel Camshaft Bearings Fail?

Camshafts are responsible for telling both your intake and exhaust valves exactly when to open and close. Camshaft bearings are responsible for keeping everything within very tight tolerances

Continue reading Why Did My Diesel Camshaft Bearings Fail?
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Cummins ISX Camshaft Wear Causes And Problems With ISX Engines

Are you hearing a sudden engine knock or is your engine running rough? These can be signs that your camshaft is failing. Replacing a camshaft can be an expensive and frustrating repair. Especially if it needs to be done outside of an engine overhaul.

Continue reading Cummins ISX Camshaft Wear Causes And Problems With ISX Engines
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4 Signs You Need To Replace Your Diesel Engine Cylinder Head

WHAT IS THE FUNCTION OF A CYLINDER HEAD? Your cylinder head is a critical part of your diesel engine. Along with the head gasket, it creates the combustion chamber that allows the combustion process to occur properly.

Continue reading 4 Signs You Need To Replace Your Diesel Engine Cylinder Head
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The 3 Most Common Cummins ISX Issues

The ISX diesel engine by Cummins is one of the most popular engines on the road today. The first ISX was produced in 1998, as a response to the EPA’s tighter emissions restrictions. It soon replaced the N14, the other workhorse engine produced by Cummins.

Continue reading The 3 Most Common Cummins ISX Issues
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VGT Actuator Failure In Cummins 6.7L

Is your truck showing signs of low boost, lag, sticking turbo vanes, or throwing actuator failure codes? Rob from HHP’s Technical Sales is here to discuss a viewer’s question on a failing Cummins 6.7L turbo actuator.

Continue reading VGT Actuator Failure In Cummins 6.7L
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6 Common Issues with Caterpillar C15 ACERT Cylinder Heads

Over time we’ve noticed similar questions related to common issues with Caterpillar C15 ACERT cylinder heads. In this post we’re covering those symptoms, why it’s happening, and what solutions we have for you!

Continue reading 6 Common Issues with Caterpillar C15 ACERT Cylinder Heads
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7 Reasons You Have Low or No Compression In Diesel Engine Cylinders

As we talked about in an earlier post, there are many things that could lead to an engine failure or the need for an engine rebuild. One such indicator is low or no compression in your engine cylinders.

Continue reading 7 Reasons You Have Low or No Compression In Diesel Engine Cylinders
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Navistar HEUI High Pressure Oil Pump Failure

We know how frustrating it can be when your equipment fails and you’re facing down time and lost profits. And paying those high OEM dealer prices only makes it worse.

Continue reading Navistar HEUI High Pressure Oil Pump Failure
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Common Rail Injector Symptoms and Failures

Whether you’re on the road or in the fields, we know that an engine failure in your diesel engine is more than just a minor inconvenience. It means lost time and lost profits. And if it’s a failure in your fuel system, you can be looking at thousands of dollars in repairs.

Continue reading Common Rail Injector Symptoms and Failures
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Camshaft Failure Causes

Is It Camshaft Lobe Wear Or Damage? We all know how important camshafts are to the function of your diesel engine, and when they fail it can spell big trouble. Whether you have a flat tappet or a roller camshaft, you’re at risk for one of the most common causes of camshaft issues: lobe wear or damage.

Continue reading Camshaft Failure Causes