Replacing A Fuel Filter

Is My Fuel Filter Clogged?

Is your car hemming and hawing more than a politician in the Iowa primaries? Does it hesitate, stall, or lag when you put the petal to the metal? If these symptoms are new, a clogged fuel filter is the likely culprit.

Fuel filters become obstructed due to dirt or rust in the fuel tank, and by debris from the normal deterioration of the fuel line. The fuel filter keeps contaminants out of your vehicle's engine.

All fuel filters need occasional changing as a part of regular car maintenance. Some cars tell you how often, but most don't. It needs to be replaced yearly, especially if your car's got a lot of miles; if you use cheap gas or gas with alcohol in it; drive on a lot of gravel; or do anything else that might help clog things up.

Nobody gets off easy. Even if you have a new car with a "lifetime" filter, it'll still need to be replaced once in a while, at least every 30,000 miles. Further, you can't tell from looking that a filter's clogged. Blow through it; if that's hard to do, then it needs to be replaced.

Safety Disclaimer

This article provides a basic description of the process of changing a fuel filter. It doesn't cover every kind of car or situation, so check out your vehicle's service manual.

First, fuel is flammable. Repeat: fuel is flammable. Take these precautions to prevent turning everybody into human charcoal:

  • Turn off the car before you work on the fuel system AND remove the fuel pump fuse or relay.
  • Smoking's extra life-threatening while working with fuel, so don't do it.
  • If you are working in an enclosed garage, make sure there is adequate ventilation.
  • Gasoline is a serious skin irritant; wear petroleum-resistant gloves, like like nitrile, while handing fuel or fuel lines.
  • Automotive fuel is also a known carcinogen, so avoid breathing fumes or prolonged exposure.
  • Clean up any spills immediately and dispose of any gasoline or fuel-soaked rags and the old fuel filter properly. Be sure to handle the old fuel filter carefully, as it will still contain a small amount of fuel.

Locating the Fuel Filter

Look at your manual to find your fuel filter, then get these things ready:

  • Several clean, dry shop rags.
  • Tools to change your specific fuel filter.
  • Extra hose if your filter is of the type that utilizes standard rubber hose and screw clamps
  • Correct fuel filter for your make and model vehicle.
  • Petroleum-resistant gloves.
  • Proper eye protection.

Changing the Fuel Filter

The first steps in replacing your fuel filter depend on the type of fuel pump. Determine whether your vehicle has an electric or non-electric fuel pump, then follow the directions below

Electric Fuel Pump

  • Remove the fuel pump fuse or relay in the main fuse box.
  • Start the engine and allow the motor to run until it stops by itself.
  • Turn off the ignition and remove the key from the starter.

This drains the fuel in the line and relieves the higher fuel pressure in an electric fuel system. If the line is not drained, the pressurized fuel will spray into the engine compartment, creating a potential hazard.

Non-Electric Fuel Pump

For a non-electric fuel pump system, you will not be able to run out the fuel; however, the pressure in the fuel line will be much lower than that of an electric fuel pump system. Because you will not be able to run out the fuel, there will be a larger quantity of fuel spilled but, because it is not under as much pressure, it will be easier to contain. Just be sure to have your shop rags handy.

Out with the Old, In with the New

If the filter is underneath the vehicle, be sure to take proper precautions before going under the vehicle. Either use ramps approved for the weight of your vehicle, or use floor jacks and stands.

Always set the parking brake and use wheel chocks. Never get under a vehicle which is supported by jacks alone. Always use jack stands to support the vehicle.

Here are the steps to remove the old fuel filter and replace it with the new fuel filter:

  • Place a shop rag under the existing fuel filter and disconnect the filter using the proper tools. Your filter may utilize a "quick connect" system. If you are unsure of the operation of this system, you should find out the proper way to remove the filter and if there are any special tools necessary.
  • Remove the existing fuel filter as shown in the vehicle's service manual. Check the filter to make sure it is facing the right direction.
  • If the existing fuel line hose is cracked, frayed, or if it is damaged when you remove the filter, replace it at this time using the extra hose you purchased with the filter.
  • Once the new filter has been installed, replace and tighten the clamps, if present.
  • If you have an electric fuel pump, re-install the pump fuse.
  • Dispose of the old filter and rags appropriately. Do not leave the old filter or any gasoline-soaked rags out once you have reconnected the battery.
  • Attempt to start the engine. It may take more that one try as the filter fills up with fuel.

Congratulations, you've just changed your fuel filter! Your vehicle's performance should increase substantially. However, if you continue to experience problems with acceleration, contact a professional mechanic.

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