Diesel Fuel Contamination

Storing fuel can be tricky. The backup fuels used to operate generators for emergency use should always be carefully maintained. So should any fuel that’s being stored for a sizeable length of time. If you’re in charge of a fleet of vehicles or any kind of backup system, take note! You or an employee should be making sure that the fuel you’re using is not contaminated in any way. You may get diesel fuel contamination

Indeed, water and microbial growth problems can become a real issue if you’re not practicing fuel maintenance and checking it on a regular basis.

Diesel Fuel Contamination may be contaminated by microbes, fungus, and bacteria, there are signs which indicate that you might be right. Look for these things.

  • Filter replacement 

    Have you found the need to replace filters much more often than your manufacturer suggests or more often than you used to do? If so, that could be a sure indication that contaminants are present.

  • Fuel injectors 

    Similar to what’s happening with your filters, your fuel injectors may also need to be cleaned or replaced more often if your diesel contains bacteria or other unwanted contaminants.

  • Nasty odor 

    You know that rotten egg smell? Well, it could be coming from your generator or anywhere else you’re using backup fuel. Microbes can give off sulfuric acid byproducts that produce that terrible odor.

  • Rings and cylinder liners

    If you find that your rings and cylinder liners are wearing out faster than they should be, it could be because acidic byproducts from microbes are causing corrosion. Furthermore, deposits from these byproducts could also wear through the rings and liners, causing holes.

  • Discoloration of fuel

    Fresh #2 diesel should be a neon-like bright yellowish green color. If it turns dark, there’s a good chance that it’s been contaminated.

  • Fuel consumption

    Do you notice an increase in the amount of fuel you’re using? If so, it could be because contaminated fuel doesn’t burn clean. That means your fuel consumption rate will likely increase.

  • Smoke at startup 

    When an engine cannot completely combust the fuel, which is often the case when it’s contaminated with byproducts caused by the microbes, you’ll see black smoke at startup.

It’s important to understand that some of these problems will be readily apparent. Others will demand a careful check. In addition, some are more common in vehicles that use diesel. Others will likely be observed in fuel storage and backup systems.

Nonetheless, it’s important to note that microbial contamination is a huge cause of problems in stored fuel of any kind. As a matter of fact, it causes expenses that can be avoided if the proper steps are taken to avoid the formation of contaminants.

How do I keep Diesel Fuel Contamination out?

The easiest way to avoid microbial diesel fuel contamination is to keep water out of your storage tanks. Water buildup can be controlled with certain additives. Stopping the buildup before it starts is obviously ideal. However, if you do develop a problem with microbes, you need to kill them with a biocide. There are a number of such products on the market. Ask your diesel provider or tank manufacturer which is best for your needs.

Of course, periodic testing for microbes can be an even better option. Fuel samples can be taken from your system at regular intervals to determine whether contaminants are present. These tests can give you a clear picture of whether you do indeed have microbial diesel fuel contamination and to what extent. In addition, testing can help you know if you’ve solved the problem once treatments are administered.


At Western Oil Services, we’re experts in fuel and fluid storage.  We can assist you in keeping your fuel supply clean and free of microbes, fungus, and bacteria. Our experts service underground or above grade storage tanks and piping as well as dispensing equipment for retail customers, and commercial grade dispensers for card-lock and fleet operations. We also offer preventive maintenance inspections. These can help keep your fuel systems running efficiently.

For more information about Western Oil Services, call us at 800-663-2097.