Change Your Fuel Filter
Your fuel filter is one of those engine components that may only cost $10 or $20, but can protect your engine from thousands of dollars in damage if you change it regularly. Fuel filters protect some of the very delicate parts of your engine. Carburetors and fuel injection systems can be clogged up by the tiniest of particles, so a properly functioning fuel filter is very important. If your fuel filter starts to get clogged up, the fuel trying to flow through the filter to your engine gets stuck in line like soccer moms at a 5 am Thanksgiving Day sale.
It only takes a few minutes to replace your fuel filter, and it should be replaced once a year on the average commuter vehicle. Replacing your fuel filter should be part of your car's regular maintenance schedule.
Step 1. Relieving Fuel System Pressure
Before you begin the job of replacing your fuel filter, you must relieve the pressure in your fuel system. A fuel injection system operates under very high pressure. If you don't release this pressure before you start unscrewing fuel lines the result can be explosive. Do this before you attempt to change the fuel filter.
To release the pressure in your fuel lines (and fuel filter) you'll need to locate the fuel pump fuse in the fuse box. If you don't have a fuel pump fuse, find the relay that operates the fuel pump. Once you've found the fuel pump fuse or relay, start the car. With the engine running, pull the fuse or relay out. If you pulled the right one, the engine will quickly die. Since it's using all of the pressurized fuel in the system, the fuel lines won't be pressurized when you crack the fittings on your fuel filter.
Step 2. Disconnect the Fuel Lines from the Fuel Filter
Now that you've relieved the fuel pressure you can remove the old fuel filter. If you didn't do this yet, you must go to the previous step and do it. Very dangerous!
If your car has fuel injection (most do these days) find two open end wrenches* that are the right size for the fuel filter fittings. They will be two different sizes in most cases. With the wrenches in place, put a rag over the fitting to separate your head from the fuel lines. This will further protect your eyes in case there is some pressure in the lines.
Hold the wrench that fits on the actual filter, and turn the other wrench counter clockwise until the special bolt (part of what's called a "banjo fitting") comes out. Slide the fuel line off the bolt and set the bolt aside. Now do the same for the other side of the fuel filter.
Step 3. Remove the Old Fuel Filter
With the fuel lines disconnected from the fuel filter, you can remove the old fuel filter from the car. Most will be held in by a clamp that can be released using a flat head screwdriver.
Step 4. Change the Fuel Filter Washers
Remember those special fuel line bolts you carefully set aside? Sitting on those will be a special pressure washer. They are usually either copper or aluminum. Remove the old washers and replace them with the new washers that match. The washers are usually different from one side of the fuel filter to the other. You'll place one washer on the bolt before you slide the fuel line on, and one after.
Step 5. Install the New Fuel Filter
Installation of the new filter is the opposite of removal. Don't forget to put the fuel pump fuse or relay back before you try to start the car. Now you've changed your fuel filter and can enjoy peace of mind and better gas mileage.
