When a diesel repair takes longer than it should, most people assume it’s the part.
Backorder. Shipping delay. Wrong item.
But in a lot of cases, that’s not where the problem starts.
👉 The delay starts with the process behind getting the part. And that’s what slows everything down.
Continue reading Your Diesel Parts Supplier Might Be Slowing Down Your Repairs (Here’s How)Core charges are commonplace in the diesel engine industry, but surprisingly, many customers don’t know what they are. If you’re one of our many curious customers, we’ve compiled this handy guide on core charges. We recommend that anyone planning on buying replacement parts check it out!
Continue reading What is a Core Charge?Diesel engines may look complicated from the outside, but most of their major systems work together toward one goal: turning fuel, air, compression, and heat into usable power.
Unlike gasoline engines, diesel engines do not use spark plugs to ignite the fuel. Instead, a diesel engine pulls in air, compresses that air until it becomes extremely hot, and then injects fuel into the cylinder. The heat from compression ignites the fuel, forcing the piston downward and turning the crankshaft.
That process is called compression ignition.
Modern diesel engines are more advanced than ever, but the basic systems remain the same. Whether you are working on a Caterpillar, Cummins, Detroit Diesel, International/Navistar, Paccar, Mack, Volvo, John Deere, Ford, Mercedes-Benz, Chevy/GMC, Dodge, or Perkins engine, the major parts all have specific jobs to do.
Ordering diesel engine parts should be simple.
Find the engine information, look up the part, place the order, and get the truck back together.
But in the real world, engine identification can get complicated fast.
A customer may have one number from an ECM report, another number stamped on the engine block, another number on the valve cover data place, and still another number cast into a component. If these numbers do not match, it can lead to the wrong part being ordered – even when the customer believed they were using the right information.
This is why Engine Serial Number (ESN) Verification matters.
The ECM can be helpful, but it should not always be treated as the final authority. If the ECM has been replaced, reflashed, cloned, or programmed with information from another engine, the data it reports may not match the physical engine in the truck.
Detroit recently unveiled its new Gen 6 heavy-duty engine lineup, including the:
with production beginning in January 2027 for the DD13 and DD15, followed by the DD16 in January 2028.
When a diesel engine comes in with a problem, experienced technicians don’t start by picking parts. Instead, they start by asking why the failure happened in the first place. However, not every failure is immediately obvious without proper inspection.
They start by asking:
What caused the failure in the first place?
Because replacing parts without understanding the root cause is one of the fastest ways to create repeat repairs.
This is the approach used by experienced diesel professionals at Highway and Heavy Parts – where real-world experience drives every recommendation.
Continue reading What Diesel Techs Actually Look For Before Recommending Engine PartsModern diesel engines are cleaner and more efficient than ever before, but they’ve also become far more dependent on electronics. Today, a relatively small component inside your Diesel Exhaust Fluid (DEF) system can take an otherwise healthy truck completely out of service.
One of the most common examples is the DEF header assembly.
If the DEF header fails—or if the Engine Control Module (ECM) receives inaccurate information from it—the truck may begin a series of emissions derates that reduce engine power and vehicle speed until repairs are made.
For fleets, owner-operators, and repair shops, that means lost productivity, missed deliveries, and unnecessary downtime.
That’s why Highway and Heavy Parts now offers DuraWRX™ DEF Management Solutions by Shaw Development—premium DEF headers and sensors engineered specifically for demanding commercial diesel applications and backed by an industry-leading 2-year warranty.
DuraWRX DEF Header Assembly by Shaw Development
Many people think the DEF tank simply stores fluid.
In reality, the DEF header is one of the most important components inside the entire Selective Catalytic Reduction (SCR) system.
A modern DEF header continuously monitors:
| DEF Level Measures how much fluid is in the tank. |
DEF Temperature Helps manage cold-weather operation and thawing. |
| DEF Quality Verifies proper fluid concentration. |
Heating Function Supports DEF flow during freezing conditions. |
| Fluid Pickup Draws DEF from the tank for system use. |
ECM Communication Sends critical data to the engine control system. |
The ECM depends on this information to determine whether the emissions system is functioning correctly.
If any of that information becomes inaccurate—or communication is lost—the ECM cannot verify emissions compliance. Instead of assuming everything is fine, it begins protecting the system by progressively limiting engine performance.
|
DEF Basics Learn what Diesel Exhaust Fluid does, how SCR systems use it, and what happens if DEF runs out. Read the DEF guide |
|
Sitting Too Long Learn how fuel degradation, DEF crystallization, moisture, and internal engine issues can show up after a truck sits. Read the diesel storage guide |
Unlike many engine failures, DEF system problems often have nothing to do with the mechanical health of the engine itself.
Your truck may continue running perfectly while a sensor begins reporting inaccurate information.
Eventually, the ECM responds by initiating an emissions derate.
This usually progresses through several stages:
| 1 Warning Light |
2 Fault Codes |
3 Engine Derate |
4 Reduced Speed |
5 Truck Down |
The actual replacement component may represent only a fraction of the repair cost. The real expense often comes from technician labor, missed deliveries, idle equipment, and lost revenue.
DEF components operate in one of the harshest environments on the truck.
They’re constantly exposed to:
Over time, these conditions can affect electrical connectors, heating elements, sensor calibration, seals, and internal electronics.
Some of the most common causes include:
Replacing the first component mentioned by a fault code isn’t always the right repair.
A proper diagnosis should include:
This approach helps prevent unnecessary parts replacement and repeat repairs.
Highway and Heavy Parts partners with Shaw Development, one of the industry’s leading manufacturers of DEF management systems, to provide premium aftermarket solutions for commercial diesel engines.
DuraWRX components are engineered to meet or exceed OE specifications while helping fleets reduce downtime and improve long-term reliability.
| OE-Style Fit Designed for straightforward replacement. |
Commercial-Duty Design Built for demanding diesel applications. |
| Sensor Accuracy Supports reliable DEF system readings. |
Corrosion Resistance Helps withstand moisture and road conditions. |
| Technical Support Backed by HHP application help. |
2-Year Warranty Provides added confidence in the repair. |
Highway and Heavy Parts offers a growing lineup of DuraWRX DEF management components, including:
Whether you’re repairing a single truck or maintaining an entire fleet, our ASE Certified Technicians can help verify the correct application before you order.
Modern emissions systems have become one of the leading causes of unexpected diesel truck downtime—but many repairs can be completed correctly the first time with proper diagnostics and quality replacement components.
Highway and Heavy Parts combines premium DuraWRX DEF management solutions with experienced ASE Certified Technical Support to help repair shops and fleet operators minimize downtime and restore dependable operation.
Call 844-304-7688 or visit highwayandheavyparts.com to find the right DuraWRX DEF components for your application.
From diagnosis through delivery, we’re Highway and Heavy Parts.
Vehicle emissions regulations did not happen all at once.
They developed over decades as engineers, regulators, and manufacturers responded to air quality problems caused by hydrocarbons, carbon monoxide, nitrogen oxides, particulate matter, and later greenhouse gas emissions.
For diesel engines, the biggest changes came when regulations began focusing more heavily on particulate matter, NOx, fuel sulfur levels, and aftertreatment systems.
Continue reading History of Vehicle Emissions Regulations: From Smog Controls to Modern Diesel Standards
One of the biggest advantages of a Variable Geometry Turbo (VGT) isn’t just efficiency – it’s how it controls airflow at low engine speeds.
Because of this, VGT turbos can improve performance across a wider RPM range.
However, when that system stops working correctly, the engine feels completely different – and performance drops fast.
Continue reading VGT Turbo Advantages (What Makes Variable Geometry Turbos Better?)If your diesel engine keeps clogging fuel filters, losing power, stalling, or pulling dark sludge from the tank, you may hear someone say you have “diesel algae.”
That term is common, but it is not technically correct.
Diesel fuel algae is usually not algae at all. True algae needs sunlight to grow, and fuel tanks are dark environments. What people call diesel algae is usually microbial contamination made up of bacteria, fungi, yeasts, mold, and biofilm living in the fuel system.
This contamination is often called diesel bug.
The problem starts when water enters the fuel tank. Microbes live in the water and feed on hydrocarbons in the diesel fuel. Over time, they create dark, slimy sludge that can plug filters, restrict fuel flow, damage injectors, corrode tanks, and leave equipment stranded.
Continue reading Diesel Fuel Algae: What It Is, How to Treat It, and How to Prevent ItDiesel engines are known for low-RPM torque, strong pulling power, and durability under load.
Because of that, the transmission behind the engine matters.
A diesel transmission has to manage:
The biggest difference between automatic and manual transmissions is how power gets from the engine to the wheels and how gear changes are controlled.
For diesel trucks, there is also a third category that matters: automated manual transmissions.
Continue reading Automatic vs Manual Transmissions in Diesel Trucks: What’s the Difference?
When it comes to diesel engine performance, most people focus on major components: turbochargers, pistons, cylinder heads.
But one of the most overlooked factors in engine performance, efficiency, and longevity is fuel injector balance.
Specifically, how closely each injector matches the others in fuel delivery.
That’s where flow-matched fuel injectors come in.
Continue reading Why Flow-Matched Fuel Injectors Matter in Diesel Engines (And When They Actually Make a Difference)
