Signs & symptoms of a bad fuel filter

Refuelling by gasoline of the modern car image by terex from

When the fuel pump in your vehicle pulls gasoline or diesel from the tank to the engine, the fuel line runs through a fuel filter that traps any debris that may be in the fuel so it doesn't damage the motor. Like any kind of filter, it occasionally needs to be changed. When it gets too dirty it can cause your car to have several troublesome symptoms that could leave you stranded.

Doesn't Start

If you turn the key to your car and the engine will not turn over, there is a chance that the cause of the failure to start is a lack of fuel reaching the carburettor or injectors. When the car cranks but the engine won't fire, it is a sign that there is a problem with the fuel filter. A blockage in the filter will prevent fuel from being pumped from the tank to the engine, causing the car to crank but not actually start.


Sometimes a car will operate normally with a fuel filter that is on the verge of becoming completely clogged. If you are travelling at normal to higher rates of speed the fuel may have trouble flowing though the line because of a dirty filter. Since the higher speeds require more fuel supply to the engine, a partially blocked filter will prevent the vehicle from getting the power it needs from the fuel. This will result in sputtering while driving. Changing the fuel filter in this instance is important to prevent complete shutdown.


While accelerating from a stop sign or red light, you may feel a hesitation or loss of power as the car gains momentum. This can be caused by a lack of fuel flowing to the engine, and may indicate a bad fuel filter.

Manual Test

One of the best ways to find out if your fuel filter is bad is to remove it and test it. If the cause of the problem is in fact a clogged filter, it will be easy to find out. Remove the filter, usually accessible along the fuel line beneath the car, and try to blow through it. If it is difficult to force air through the filter, then it is a sign that it is time to replace the filter. Air, like fuel, should be able to pass through the filter with ease. Visual inspection may be enough if debris is visible in the filter.

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