(Updated on September 9, 2021)
A fuel filter removes particles, impurities, and contaminants from the fuel that would otherwise enter the engine’s internal combustion chamber.
When you pump fuel into your fuel tank, you introduce several opportunities for debris to enter the engine. Particles around the gas cap can fall into the tank. There also may be rust particles or sediment in the fuel tank itself.
When your fuel enters the tank, it is going to get mixed with these debris particles. Without a fuel filter, these particles could easily clog the delicate fuel injectors or even enter the combustion chamber. This is going to cause a problem if the contaminated fuel were to enter the engine.
These small particles may otherwise reduce engine performance and possibly shorten the engine’s lifespan. Therefore, the fuel filter has a very important job to do in the fuel system so that the engine can stay strong and function well.
How a Fuel Filter Works
Fuel filters are very similar to engine oil filters. Fuel goes in one end of the filter and is passed through a filter element (usually filter paper). The filter paper catches particles and contaminants, allowing clean gasoline to exit the other side.
Many fuel filters are designed with a flow direction that minimizes the filter restriction. Make sure to look for this arrow when you go to install a new fuel filter.
Top 5 Bad Fuel Filter Symptoms
If you ever go to get your oil changed at a professional auto servicing location, the service person will periodically tell you that you need to change your fuel filter. The reason for this is that fuel filters do not last very long in a vehicle.
You may be able to drive up to 30,000 miles before you need to change your fuel filter although the change interval may be longer for newer vehicles. After that, your fuel filter may become too clogged to do its job properly. You will need to replace it right away or else suffer the consequences.
Here are five of the most common signs you have a bad fuel filter in need of replacement.
1) Bad Gas Mileage
Your gas mileage will get worse as your fuel filter gets worse. Perhaps you have a clogged fuel filter which is limiting the amount of fuel that can flow into your engine.
If the engine doesn’t get enough fuel, it will require a faster flow of fuel to get pumped into it so that it can sustain the driving demands placed on it. This means more fuel consumed than normal.
2) Check Engine Warning Light
The engine control unit will be able to detect when there is a problem with the fuel system. Any kind of problem that affects the engine like this will cause the Check Engine warning light to activate on the dashboard.
A bad fuel filter can cause this to happen too because it negatively affects the flow of fuel going into the engine.
3) Weak Engine Power
A clogged fuel filter is a restriction in the fuel system. If you step on the gas pedal and the vehicle does not accelerate immediately or at all, then you may have a bad fuel filter among other things.
When the engine requires more fuel, a clogged or worn out fuel filter will prevent that fuel from getting there fast enough. This will limit the engine’s ability to accelerate your vehicle when you want it to.
4) Engine Won’t Start
Sometimes your engine will not start at all if you have a faulty fuel filter. Perhaps there is not enough fuel entering the internal combustion chamber to make the engine functional.
The problem may start out as hard starting but then turn into a problem where it doesn’t ever start.
5) Engine Stalling
You may be driving along on the road and then suddenly find that your engine is stalling. This is when the engine stops turning, or its RPM is greatly reduced without any just reason.
This will stop the engine from functioning, which is the worst thing that can happen while you’re driving.
Fuel Filter Replacement Cost
The replacement cost of a fuel filter is between $50 and $170. The fuel filter part will only be around $15 or $70 while the labor cost will be between $45 and $100.
It is not a very expensive or difficult job to do at all. That is why most oil changing shops and businesses will offer to do this service because it can be done that quickly.
How Long Does a Fuel Filter Last?
Fuel filters will last a very long time. Depending on the vehicle you drive, quality of your fuel, and the amount of particles that have made their way into the fuel tank, your fuel filter could last anywhere from 30,000 to 75,000 miles.
Check your owner’s manual to see if the manufacturer includes an explicit interval for fuel filter replacement.
If you have over 100,000 miles on your engine and the fuel filter has never been replaced, now might be a good time to search for a new one. A clogged fuel filter is a cheap fix that can lead to more expensive problems down the road.