4 Common Rail Diesel Problems? (Troubleshooting)

Common Rail Diesel Problems

Despite the durability that you get with a common rail diesel engine some things are bound to go wrong eventually. You need to know what to look out for when issues do start cropping up, and what you will have to do to fix them.

In this article, we’re going to outline some of the biggest common rail diesel problems that your vehicle is likely to face in its lifetime, how to identify each one, and what needs to be done to get the engine up and running again.

What Is A Common Rail Diesel Engine?

If you want to solve an issue with your engine, you first need to understand exactly which type you are dealing with. Therefore, we should go over what a common rail engine is before we get into the problems that you might encounter with one.

A common rail diesel engine is different from other systems because the fuel is delivered to individual fuel injectors via a common rail, and from there the fuel is directly injected into the combustion chambers.

This is different from the conventional systems, which typically deliver the fuel through a low-pressure pump that connects to a unit injector. You can check your vehicle’s manual to see what kind of engine you have, or you can take a look under the hood to see if you can spot the common rail itself.

Read also >> How Does A Common Rail Diesel Fuel System Work? (Incl. Video)

Read also >> What Does Common Rail Diesel Engine Mean? (Benefits + More)

What Are The Advantages Of A Common Rail Diesel System?

The common rail system is actually a relatively new innovation that was popularized in the 1990s. Since then, however, it has become the most popular system that is used in commercial diesel vehicles because it comes with a lot of advantages.

The benefits of this technology include:

  • Improved performance
  • Low consumption and reduced emissions
  • Lower noise levels
  • Adaptable for modern vehicles
  • Increased efficiency

This means that engines using a common rail fuel injection system are quieter, better for the environment, more powerful, and more efficient.

They don’t come without their issues, though, and you may come across one of a number of different problems throughout your engine’s lifespan.

4 Common Rail Diesel Problems

Now that we know what this kind of engine is, and a little bit about how they work, we can talk about what might go wrong.

1.  Fuel Contamination

Perhaps the most common of all the problems a rail diesel engine can face is caused by fuel contamination. Due to the fact that the common rail fuel system is comparatively modern and relies on extreme speeds and pressures, they need to be run with the cleanest fuel possible.

Even a slight reduction in fuel quality can lead to significant issues.

Contamination is usually caused by water, particulates, petrol, or other non-diesel liquids. It is likely to result in some damage to the components in your system, in particular the injection pump, fuel injectors, pressure sensor, or control components. You will also probably notice a reduction in performance and other symptoms can include low or high rail fuel pressure and error messages from sensors of injectors.

All too often, people will replace damaged components in their rail engines without addressing the root cause, and that cause may well be contaminated fuel.

How To Solve:

Solving this problem depends on how much damage has already been done. Ultimately, many of the component parts may need replacing, and you will certainly want to flush the whole system.

That means completely draining the fuel tank, giving it a thorough clean, then disposing of the contaminated fuel and replacing it with clean, high-quality diesel.

2.  Carbon Deposit Build-Up

One of the negatives of using a diesel engine over a gasoline engine is that they can be quite particular about how they should be used. In order to function properly, a diesel engine should be brought up to temperature on a regular basis, which means relatively frequent long journeys.

If you are making a lot of short trips or idling excessively in traffic, then deposits can build up throughout the system.

These typically occur in the:

  • Combustion chamber
  • Turbocharger
  • Particulate filter
  • Exhaust

These deposits can lead to a loss of power, increased emissions, and lower fuel economy.

How To Solve:

A fuel system cleaner can help to clear out any significant deposits that have built up in your common rail engine, and they are pretty easy to get your hands on and use.

For more significant problems, you may need to give the system a manual clean.

3.  Component Erosion

Another significant problem to look out for is the erosion of certain component parts – most notably the ball seat and nozzle.

This issue is more likely in these engines due to the significant amount of pressure that the system is under, and once these parts wear down then it can severely affect how well the engine runs.

If the high-pressure ball seat erodes in any way, then the ball will not properly seal. This means that the return rate will be higher, and fuel will not be efficiently injected into the combustion chamber. You might notice vibration while idling, reduced performance and problems starting.

If the nozzle wears down, then the fuel will seep. This will lead to lower fuel economy and might even see blueish-white smoke when you are idling.

How To Solve:

If any of your component parts are eroded or worn down, then they will need to be replaced. There is little else that can be done at this point, but you can reduce the likelihood of the problem returning.

Erosion typically occurs when the filtration in your engine is poor, the fuel quality is low, and the vehicle is not being regularly maintained.

4.  Solenoid Valve Problems

One particular component that can fail in a few different ways is the solenoid valve, which is the electro-mechanical valve that’s used to control the flow of fuel within the engine. The combination of its electronic and mechanical parts means that there are a few different issues that can arise.

  • Coil failure. If the wrong voltage is applied to the solenoid coil, then it can be damaged or burn out completely. This can also be caused by liquid or sediment coming into contact with the coil itself. If it has failed, then no fuel will be able to get into the engine.
  • Valve Failure. Overly high pressure within the system and sediment in the valve can cause it to become damaged, or lead to the deformation of the seals. This will usually result in leaks as the valve will no longer seal properly.

How To Solve:

If your solenoid coil has burnt out, it will need to be replaced. The same is also true for a solenoid valve that has been damaged in any way.


So, what are the most likely problems you are going to face with a common rail diesel system? Fuel contamination is possibly the biggest, and this can have a big knock-on effect – leading to damage throughout the system.

You might also see a build-up of carbon deposits, and both of these problems will typically require a full system clean.

Components within the system can also become damaged or fail. Typically, these might be the ball seat and nozzle or parts of the solenoid valve. These will need to be replaced if they are no longer functioning properly.



Stephan K.

I have been working as a mechanic for over 13 years and have been deeper into advanced automotive diagnostics for some years.

Recent Posts

error: Content is protected !!