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How Often Should Fuel Filters Be Changed on a Diesel Engine?


Diesel equipment filters are an important part of keeping your equipment in working order. A diesel fuel filter is especially important for a diesel engine, since diesel fuel is naturally quite dirty. But you might be asking yourself, “How do I know if my diesel fuel filter is bad?” and “When is it time to change it?”

The answer to both questions depends on several factors which we’ll discuss in the rest of this article. It’s important to keep in mind that filter life is highly dependent on the equipment and operating conditions, so it is vital to follow the manufacturer recommendations for filter replacement for your diesel engine fuel filter.

 

What Are Some Factors That Affect the Diesel Fuel Filter Interval?

The fuel filter interval dictates the amount of time between filter changes. Most vehicles and machinery that use fuel filters will have a recommended fuel filter interval written in the owner's manual or maintenance guide. However, these intervals are approximate guesses based on “standard” usage.

There are a variety of factors that affect when your filter needs to be changed. These include:

  • The effort of your machine.
For heavy-duty applications (like a semi-truck pulling a heavy load up a steep incline), more fuel is being used, so the filter is working harder.
For light usage (like an unloaded semi on flat terrain), less fuel is required, and the filter will last longer.

  • The grade and impurities in your specific diesel fuel.

  • The machinery itself and how resistant the fuel system and engine are to small particles.

  • The temperature outside, and other weather conditions affect the viscosity of the fuel and wear on the filter.

To give a specific example, let’s look at how often to change a fuel filter in a diesel tractor under two different sets of conditions. In case one, the tractor is used in the cold to plow heavy snow on steep hills with low-quality diesel fuel. It may require a fuel filter change after only 400 hours of run time. That same tractor in the summer may pull a wagon for hay rides on flat ground using high-quality fuel and not need a filter change until 900 hours of operation.

In most cases, you need to change a diesel fuel filter when it’s dirty enough to compromise performance or potentially damage the engine. With that being said, let’s go through what this filter does that makes it so important and what you should look for to know when it's time to change the filter.

 

What Are the Symptoms of a Dirty Diesel Fuel Filter?

The function of a fuel filter in a diesel engine is to stop fuel impurities from getting into the engine or parts of the fuel system where they can cause problems. Once the filter becomes so dirty that it can no longer filter fuel effectively, these impurities will begin to negatively affect machinery performance. It’s critical to recognize these symptoms early on so you can change the filter before larger problems occur. Some of the easiest symptoms of a dirty diesel fuel filter to spot are:

  • Poor Engine Performance
    • A decrease in gas mileage may occur.
    • You may notice a decrease in power or responsiveness.

  • Difficulty Starting
    • A clogged or partially clogged fuel system will make starting difficult or impossible.
    • There are other causes for this, so it's important to check more than the fuel filter if this happens.

  • Unusual Sounds
    • Any weird noises from your heavy machinery should always be investigated.
    • A fuel pump can start to make an unusual noise under high workloads, if there is a blockage in the fuel system.

  • Shaky Ride at Low Speed
    • Engines and fuel systems require the most fuel when exiting an idle or stationary state.
    • Problems with blockages will be most noticeable at lower speeds.

  • Rough Idling
    • If the diesel fuel system can’t get enough fuel through consistently, the idle will be rough.
    • It may be easier to notice this inconsistency during idle than during operation with other noises and vibrations.
 

How Long Can You Drive With a Clogged Fuel Filter?

We’ve gone through the general recommendations for when to change a fuel filter and what specific symptoms to look for to know when your diesel fuel filter needs to be changed. But what happens if you don’t notice the signs or choose to ignore them? What happens when you operate your machinery with a dirty or clogged fuel filter?

You should drive with a dirty fuel filter for as little time as possible because it can do lasting damage to your engine and fuel system and lead to costly repairs or shorten the overall lifespan of your machine. Paying close attention to the recommended lifespan of a filter and to the signs showing you a specific filter may not be working its best is very important.

Generally, heavy machinery is a big financial investment and performs important tasks. Unexpected breakdowns, towing, expensive repairs, and downtime can cause huge problems and add up to significant financial burdens. Keeping up with fuel filter replacement and other equipment maintenance can help save a lot of money and frustration. Using high-quality replacement filters that will last and keep you running at peak performance will always be a money and sanity saver in the long run.
 

Fleetguard: We Know Filters

When you want high-quality diesel fuel filters that have a proven track record and state of the art materials (like our multi-layered NanoNetⓇ media, developed in-house), you want Fleetguard. Our filters have been used and abused in heavy machinery and can hold up to everything you will throw at them. We stand behind our products so much that we offer the best warranty in the industry. To protect your heavy machines, use Fleetguard!