Common Diesel Engine Problems

Diesel Meter Common Causes for Diesel Engine Problems

It's unlikely that you'll never have a problem with your diesel engine. But when one occurs, you want to get back on the road as quickly as possible. Being able to identify some of the most common issues can help with that. There are many different reasons your diesel engine might be acting strangely, and while it can be frustrating to have it out of commission, it's better to check out your engine if you're experiencing any of these symptoms before you have a total engine failure from a problem that worsened.

This is not a comprehensive list of everything that could be causing you issues. It's just meant to give you an idea of what might be going on under the hood. If you have any questions about your specific case, it would be wise to contact your mechanic.


Common Diesel Engine Symptoms

Listed below are some of the most common symptoms diesel engines suffer from as well as some possible causes for each issue:

Black Smoke

If you notice black smoke coming from your exhaust, it's most likely because of an incorrect air to fuel ratio. This can be caused by:

  • Faulty Injectors
  • Faulty Injector Pump
  • Bad Air Filter
  • Bad EGR valve
  • Faulty Turbocharger
  • Cold Operating Temperatures
  • Carbon Build-up
  • Poor or Incomplete Combustion

Blue Smoke

Blue smoke is an indication that your engine is burning oil for some reason. Possible causes include:

  • Worn Valve Guides or Seals
  • Wear in Power Assemblies
  • Problem with the Oil Filter
  • Problems with the Turbocharger
  • Piston Damage or Wear

White Smoke

White smoke coming from your exhaust is usually caused by too much fuel, or not enough heat causing improper combustion. Some factors that might cause this are:

  • Worn Out Injector
  • Incorrect Timing
  • Low Compression

Trouble Starting or Hard Starting

Do you have problems getting your engine going? Does it seem to turn over too much before roaring to life? Here are some issues that might be causing you trouble:

  • Cold Weather Affecting the System
  • Glow Plug Issue
  • Low Compression
  • Fuel Delivery Issue
  • Battery Issues

Noise (knocking)

Engine knocking might be a sign of a serious problem and should be looked into right away before it gets even worse. A few things that might be causing the knocking:

  • Compression Issues
  • Faulty Fuel Injectors
  • Cold Operating Conditions
  • Timing Issue
  • Failed Bearings
  • Failed Wrist Pin Bushing or Wrist Pin

Lack of Power

If you notice less power in your engine, it might not just be normal wear. It would be good to take a look to see if there is a deeper problem, including some of the following:

  • Plugged Filters
  • Fuel Contamination
  • Low Compression
  • Faulty Turbocharger
  • Failing Camshaft
  • Bad Injectors
  • Bad Fuel Pump

Faltering Engine

Similarly, a faltering engine could be letting you know that there is a problem that needs to be addressed. Some things you might look for:

  • Fuel Contamination
  • Cold Start

Excessive Oil Consumption

You might notice that you're going through oil much faster than you used to. You might have a leak somewhere in you engine, but there might also be another issue:

  • Engine Age
  • Increased Demand
  • Oil Viscosity
  • Oil Change Intervals
  • Burning Oil
  • Worn Valve Guides
  • Failed or Worn Piston Rings
  • Failed Turbo Seals

For more information on excessive oil consumption, its causes, and the effects it has on your engine, take a look at our past blog, Excessive Oil Consumption Explained.

Engine Disruption or Failure

Perhaps the most noticeable indication that there is a problem with your engine is disruption or even total failure. There are many things that could cause this, including:

  • Liner Cavitation
  • Worn Bearings
  • Overheating
  • Contaminated Fuel
  • Major System Failure within the Engine


The included graphic summarized these symptoms and causes for you:

Indicators and Possible Causes Page 1 | Highway & Heavy Parts  Indicators and Possible Causes Page 2 | Highway & Heavy Parts
Download a copy here.


Some of the minor issues listed above could lead to total engine failure if left unaddressed for too long. Don't ignore the warning signs. You could prevent a minor repair from becoming major if you catch it early.

If you do happen to experience a major engine problem that requires a rebuild, we can help! Take a look at our selection of re-ring, inframe, and out-of-frame rebuild kits.

If you'd like to request a quote on a part to help with any of your diesel engine problems, you can do so online, or you can give us a call at 844-304-7688 to speak with one of our certified technicians.