Cleaning the fuel filter is essential to keep the fuel delivery system in proper working order. By filtering out contaminants from the fuel, the filter prevents the fuel injectors from clogging and helps to maintain the vehicle's optimum performance levels.
Yes, the refinery cleans the fuel, but it absorbs many impurities during storage and transport to the local petrol station. In addition, a car's petrol tank usually contains dirt and other particles that can cause serious damage to the engine.
A clogged fuel filter can force the fuel pump to work harder and less efficiently. When you accelerate, a hungry engine uses a thin fuel mixture and can lose power. Changing the fuel filter regularly prevents these particles and contaminants from reaching the fuel injectors. Check the owner's manual for the filter manufacturer's recommended filter change interval.
Some modern vehicles use an external fuel filter, which is fitted to the fuel supply line. It is connected to the fuel tank and the fuel rail that feeds the fuel injectors. You can find the fuel filter by simply following the supply line.
Several applications now have the fuel filter as part of the fuel pump module assembly located inside the fuel tank. For these vehicles, a faulty or clogged fuel filter is also usually an indication of a fuel pump problem. Some of these you can replace the fuel filter yourself, but most you will have to replace the entire fuel pump module assembly.
In this example we will be replacing the fuel filter on a 1999 Ford Expedition. The same process applies to most Ford cars, SUVs and trucks. To remove the filter, you will need some tools. You will need some spanners, a fuel line disconnect tool, screwdriver and drain pan.
Disconnect the negative battery cable for added safety.
Use one of the following methods to relieve fuel pressure.
Press the pressure relief valve located on the fuel rail.
Remove the fuel pump fuse and start the engine. Let it run until it dies from using up all the fuel remaining in the line. Turn off the ignition switch.
Place the drain pan under the filter to collect any fuel that may have spilled. Remove the safety clips from the fuel filter and fuel line.
Slide the fuel line disconnect tool all the way between the tip of the fuel filter and the fuel line. The tool will push out the tabs that hold the fuel line in place, allowing you to separate it from the filter.
Use one hand to hold the tool against the fuel line. With the other hand, pull the line out. Disconnect the two lines and remove the fuel filter.
Loosen the worm gear clamps holding the fuel filter to the frame. Slide the filter forward out of the clamps.
Apply petroleum jelly as a lubricant to the end of the new filter or to the O-ring in the fuel line. Slide the new filter into the retaining clip and tighten the clip. Push the fuel line into the new filter until it locks into place to reconnect the fuel line.
Replace the negative battery cable.
Start the engine and ensure there are no fuel leaks.