As your engine runs, fuel is drawn through the system by the fuel pump from the tank through lines and injectors until it ends up in the combustion chamber to be ignited. It’s a precisely timed and metered journey — one that involves tight tolerances, high heat, pressure and friction. A fuel filter plays its own important role, which cannot be understated, and like any other filter, it’s not meant to last forever. At some point, it will become dirty and need to be dealt with. What then?
Purpose of a Fuel Filter
Fuel filters are added to fuel systems to remove and keep out impurities such as debris that might enter when you’re fueling up or rust that forms as a result of condensation inside steel components.
Due to all of the aforementioned tight clearances and high pressures, even small particles can start to wear down and damage components in the system, causing leaks, loss of performance, premature failure and expensive repairs. Fuel filters guard against this by trapping and holding the particulate matter. Most filter elements are made of treated paper and are rated with specific allowances, essentially telling you the size of particles that can pass through it. These ratings are measured in microns. The filter element within the outer case is usually pleated to provide more surface area and thereby enable more flow of fuel as the engine demands it.
Signs of Clogging
Unfortunately, when a filter becomes dirty and clogged, it becomes part of the problem. A clogged filter can make itself known in a number of ways, but it all comes down to the dirty filter holding up fuel flow and starving the engine of what it needs for combustion.
You may notice that the vehicle is difficult to start, has a rough idle or has trouble accelerating. Conversely, you might notice that at slower speeds the engine struggles or dies when you slow to a stop. If the situation is very bad, the engine might starve for fuel while you drive or not start up at all. You may also notice misfires and loss of performance generally, but it’s important to note that many of these symptoms could be rooted in other issues, so it’s important to pull codes with an OBDII scanner or speak with a mechanic if you’re not sure how to diagnose a clogged filter definitively.
If you’re wondering whether you should remove a fuel filter and then clean it by rinsing or blowing it out before putting it back into the system, the answer is a resounding no. Paper-element filters are meant to be changed, not reused, and the wrong fluid or air pressure could damage them or lodge particles further in. Some filter types do have metal elements with specific cleaning procedures, and some diesel filters are bowl-type, which means they accumulate water and need to be drained, but the majority of fuel filters simply need to be replaced when their time is up.
A filter’s lifespan depends on the manufacturer’s recommendation, but if your vehicle is an older model or it goes through a lot of fuel, you’ll likely want to replace it more often. Fuel filters are an important piece of engine maintenance, and they’re relatively easy to stay on top of. Be sure to replace them before they affect performance or require larger repairs.
Check out all the filters available on NAPA Online, or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on changing a fuel filter, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.
Photos courtesy of Blair Lampe.
Blair Lampe is a New York-based professional mechanic, blogger, theater technician, and speechwriter. In her downtime she enjoys backpacking wherever her boots will carry her, rock climbing, experimental theatre, a crisp rosé , and showering love on her 2001 Sierra truck.