How to check for fuel in oil – Here’s what to do

As fuel is ignited during the combustion cycle, it can enter the crankcase and be presented to the lubricating oil. The method of the plain or unburned fuel blending with the oil is known as fuel dilution. There are many grounds for fuel dilution, with most related to some sort of mechanical issue. How to check for fuel in oil – Here’s what to do – Read on!

Perhaps the most typical reason fuel dilution happens is due to a technique known as blow-by. If the elastic band’s rings are broken or filthy, they may not close correctly. These rings are designed to keep the oil and the exhaust separated and are critical in ensuring proper compression in the cylinder. This is the unwritten rule, by all means!

There are instances, mainly in diesel motors where fuel can blend with oil. If you glimpse a more increased volume of oil and its shade is more translucent on your dipstick. In that case, that can indicate that diesel fuel is in the oil. This is the unwritten rule! The alarming part of this issue is that detection and restoration can take a ton of time and action.

You can check whether there is fuel in the oil manually. However, there is also another option. Fourier-transform infrared spectroscopy is a spectacular test that most oil study laboratories employ. It can witness fuel. Yet, you must have a new oil mark and a fuel mark to know where to skim on the range. 

Table of Contents

Why is diesel fuel in oil?

There is a question that surely bugs many drivers nowadays. What is it? Why is fuel in oil and how to check for fuel in oil? To answer that question, we need to know what are the main causes of the gasoline in the oil. Let’s dive into more!

Dying injector nozzle

This next point has great significance! Usually, dying injector nozzles are the most typical reason why diesel engine gets into the oil. We should always check for this to stop the unwanted effects.

With time, the nozzle seal may wear out and the tightness will become weak. For this reason, diesel fuel will be present in the oil. This is the unwritten rule! Most frequently, the problem is that the density of its sealing ring vanishes on the nozzle itself. If more than one nozzle is failing this means that diesel fuel will get into the oil much quicker.

The spray nozzles may somewhat fail from time to time. Speaking of which, the injectors will not spray gas. Yet, thoroughly pour it into the motor. Because of this, diesel fuel might not burn fully and will get into the motor. A comparable problem is out there when the nozzle portal pressure drops. This is the unwritten rule, by all means!

Worn high-pressure pump elements

Usually, the stuff gaskets of the high-pressure gas pump can have the issue. So, there is a chance that the diesel fuel goes inside the oil. Other failing parts of the high-pressure pump may push this issue to happen. What are those parts? Those parts can be fittings, pipes, or fasteners.

Likewise, the bad plungers of the high-pressure pump do not have the required pressure. What then? In that case, the gas can get into the pump itself. From there, the gas will blend with the oil. This is true, especially for older motors. In newer engine models, this is no longer a thing.

Oftentimes, the issue can be the return components, in the copper washers out there. They might not be correctly pressed down. Or perhaps they might thoroughly leak diesel fuel.

Dying seals on the diesel fuel pump

Diesel gas pumps will consistently have at least one oil seal on them. It doesn’t matter what their design is. That does not permit the fuel to combine with oil. Fuel pumps can include two oil seals on some vehicles, as a matter of fact. What if the seals or one of the seals is worn-out? In that case, that indicates either gas or oil will flow out from a precise channel.

Weary gas revitalization system

Whether the weary gas regeneration system is not functioning properly, diesel fuel can get into the oil. Founded in electronics, the data of the DPF pressure and temperature detectors exist. The system occasionally provides fuel, which is ignited in the filter and thereby cleanses it.

utilizing regular or mid-grade fuel won't hurt your motor

Crack in the cylinder crown

An infrequent cause mainly attends in aluminum engine blocks. Diesel fuel can enter via these cracks in the motor and integrate with oil. On most occasions, the cracks can be driven by mechanics who narrow the nozzle. How? Just by not using a torque wrench when lodging them. Because of the extra power, micro-cracks may occur that can rise in time.

Cracks appear not only in the place where the injectors are lodged. Yet, likewise in the channels through which the gas is filled. These cracks are usually the outcome of a casualty, mechanical wear, etc. Hence, you need to check not only the head but also the rail and gas lines. This goes without saying!

The motor does not warm-up

Another irregular occurrence. Particularly in winter, it’s a widespread fact that diesel engine warms much slower. This is the unwritten rule! So, what if you drive short lengths or the engine does not have enough time to warm? And what happens if you have a dying thermostat? Diesel fuel will not thoroughly burn out. What’s more, it will crystallize on the cylinder walls. And from there it will already flow and integrate with the oil.

Tip: Did you know that you can also save money on fuel by driving safely and not inducing a road rage?

How to check for fuel in oil?

The result of this icky situation is that the oil will lose its effects. Also, the defense against friction will reduce. Correspondingly, the oil density will drop pushing other meaningful problems. For instance, the engine will overheat, leaks may occur, the essential force in the system will fade, and so on. Hence, diesel fuel must not be let in the crankcase!

  • Check the injectors. You can employ an air compressor to see the loss of tightness in the injector stamps. Compressed air is counted into the rail return channel, via which gas is supplied. In the area of ​​the nozzles, you need to add a little bit of diesel fuel so that in the event of a leak, the air goes through it and makes bubbles. The compressed air pressure should be of 3-4 atmospheres.
  • Replace the O-rings. Are the cracks in the spots where the injectors are? If yes, repairs are brought out in a workshop. Let’s say the nozzles are seated under the valve cover. Then, the return lines must be reviewed. Also, if necessary, pressurize before removing the nozzles to avoid unnecessary work.
  • Inspect the diesel fuel pump. Replacing the fuel pump oil seal sometimes helps solve this trouble. Review for advanced gaps in the plunger duos. Likewise, the reduction in the motor which you can see in the vehicle manual. You can likewise check and if critical get the new rubber seals on the pump.
  • Check the cylinder crown. A crack in the cylinder crown or in its fuel fence is a serious problem. It usually leads to the whole motor replacement. If the crack is tiny you can choose to weld it. Yet, as a matter of fact, this does not ensure a satisfactory result. This goes without saying!

Signs of fuel in engine oil

  • High gas consumption. If you do experience this issue then it will be rational that your car takes more fuel. Yet, with a very little quantity of fuel leak, you can’t feel elevated usage. Merely when the amount of lost fuel is higher.
  • Engine performance drops. You will see a flop of performance in many cases. When pressing the gas pedal, the vehicle accelerates gradually. When the vehicle is full, it will feel like it has no power. Lastly, this can happen when you drive your vehicle on hills for instance.
  • Dark steam from the extra pressure ease valve. Let’s say there is diesel fuel in the oil. In that case, steam with an obvious smell of diesel fuel comes out through it.
  • Deceased oil pressure in the system. What if the oil is too fluid, and its pressure is ineffective. Then, the motor will shake. And this will guide to entire deterioration and replacement.

Final thoughts

There are some reasons for diesel fuel in oil that can be rather challenging and tricky to repair. Yet, there is a way you can do this. Whether you uncover a suitable car workshop that does the job accurately. If you manage to restore this trouble don’t overlook doing an engine flush. Also, don’t forget to count on high-quality oil.