Longevity of Diesel Fuel in a Generator Tank

Preventive Fuel Maintenance for Emergency Generators

We’ve said it countless times since opening our doors in 1965 – when it comes to keeping your emergency generator running, preventive maintenance is key! This is particularly true when it comes to extending the life of your general fuel. Diesel fuel contamination can have serious consequences for your backup generator, not least of which is your generator failing in an emergency.

Diesel fuel likes heat and likes to burn- two things that an emergency generator doesn’t do all that frequently (if you’re lucky). With emergency backup equipment, there can be long periods of inactivity between emergencies and power outages, which is why we recommend exercising your unit regularly. But beyond exercising the engine and the overall unit regularly, we also recommend paying close attention to the quality of the fuel in your emergency generator. Problems can arise from contaminants and idleness. One of Duthie Power’s Generator Experts explains more in the video below:

How Long does Diesel Last in a Generator Fuel Tank

How long before diesel goes bad? Diesel fuel in a generator fuel tank can last the life of the generator, 30 to 40 years. It depends on the maintenance that is kept on the generator in the fuel tank. It’s that ongoing maintenance that will answer the question, “Is my stored diesel ready for an emergency?” It’s a matter of fuel contamination.

Fuel contamination is a major cause of premature shutdown for standby engine generator sets, fire pump engines, and other diesel engine support functions. As the length of the storage period increases, the probability of premature engine shutdown due to either clogged filters or excessive water entrainment also increases.

What causes Diesel Fuel Contamination

Fuel contamination occurs when it is exposed to something in the environment that accelerates the natural processes that attack its quality. All petroleum fuel, whether gasoline or diesel, is made of a mix of molecules of different sizes and lengths. Fuel starts with several unstable molecules – the “precursors”. Over time, these precursors look to react with other molecules and start chain reactions that, given enough time, cause the fuel to form gums, varnish, and sludge, and become dark and stratified.

As always, if you’re concerned about the diesel fuel in your generator fuel tank, we recommend bi-annual maintenance of your generator and fuel tank.

For more information on how to store diesel fuel, request a quote or give us a call at 1-800-899-3931.