DIY: Replacing Your Fuel Filter

   Compare the new fuel filter with the old fuel filter, and make sure you position it in the same way so that the fuel is flowing in the right direction. Most times there will be an arrow on the fuel filter showing you which direction the fuel flows. Put the assembly together in reverse of the way you took it apart. Before you do, though, take a quick look at the new fuel filter. Again, a little oil or white grease on the fitting will help the hoses slide on easier.

   You'll see there are two tubes coming off the fuel filter where the hoses attach. They have little nubs or ridges near the ends. Make sure to slide the rubber lines onto the fuel filter as far past the nubs as you can get them, ideally up against the fuel filter body. Position the hose clamps between the nub and the fuel filter body. Make sure they good and tight, but not so tight as to strip the screw.

   The clamps used on the fuel lines are special clamps designed to seal the hose to the fuel filter fittings. They do not cut into the fuel hose and can withstand the higher fuel pressure. Ideally they should be replaced with the new fuel filter. Do not use the worm type "mini-clamps". They will damage the hoses and a fuel leak will develop.

   One last type of fitting I want to talk about is the good old "nut and bolt" type fitting. This fitting just requires two wrenches to remove. You will see a hex fitting on the filter. You use one wrench on this hex fitting to hold the fuel filter while you remove the fuel line fitting.

   Care must be taken to not cross thread or over tighten the fitting. Make sure the fittings are tight enough not to leak, but that's it. You can use a dab of sealer or Teflon tape to help the seal. If you use Teflon tape, don't use too much because the excess could get inside the lines and block a fuel injector. Do not use any type of RTV silicone sealer because gasoline will dissolve it away.

   I would recommend using a special line type wrench. A line wrench is thicker than a regular open-end wrench and it covers ¾'s of the fitting, versus the ½ coverage of a standard wrench, reducing the chances of rounding the fitting. The extra thickness spreads the turn force over a wider area, also reducing the chances of a rounded fitting. They are very useful when working with brake lines as well. It might not be a bad idea to pick up a set.

   Okay, after you have everything reassembled and secure, crank the engine a few times with the ignition system disabled, if you can, until fuel pressure builds up. Then look over the fuel filter and fuel lines no make sure there are no big leaks. If everything is okay, start the engine and let it run for a few minutes, again checking for leaks. No leaks? Great job! Do this once a year and you'll never have a fuel filter related problem again.

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