How Often Should You Change the Fuel Filter?

by Chris Moore

You must change your vehicle's fuel filter at 50,000 miles. Subsequent filters should also be changed at least every 50,000 miles, but changing them annually is even better. This is especially true once the car is at least seven years old, because rust, debris and other contamination builds up in the fuel tank and can clog the filter faster. This will even affect filters advertised as having an indefinite life span. When changing a filter, the exact process will vary depending on your type of vehicle.

Safety Precautions

You must relieve the high pressure that the fuel system is under before you can work with the fuel filter. Open the fuse box under the hood and remove the fuse or relay for the fuel pump. Start the engine; if it won't run, crank it a couple of times to make sure the pressure is gone. If the engine starts, let it run until it stalls. Disconnect the negative battery cable. Once you have changed the filter, reconnect the cable and the fuel pump relay or fuse. To re-pressurize the system, turn the ignition key on for two seconds and then turn it off for another five; repeat this procedure up to 10 times.

Changing the Filter

The fuel filter will be located near the fuel tank, so raise and support the vehicle at its end where the gas cap is. Clean away all dirt, dust and other debris, especially near the fittings connecting the filter to the fuel lines; compressed air or carburetor cleaner will work. Some filters will be connected to the lines with screw-in fittings and nuts that you must remove. Use a flare-nut wrench on these fittings to avoid stripping them. Others will use "quick-connect" fittings, which can come in different types. Squeeze-type fittings require you to press their locking tangs together to disconnect them. For push-clip fittings, pull the locking tang out and then push the clip through the coupling. There will likely be fuel spillage as you disconnect the lines. To remove the fuel filter after disconnecting the lines, loosen its clamp with a screwdriver or remove its bolts with a wrench; it will likely be mounted by either. Mount the new fuel filter in the exact same position the old one was in, and connect the clamp or bolts. Connect the filter to the fuel lines, then re-pressurize the fuel system as described above.

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