How to Use Gas Tank Sealer to Stop a Fuel Leak

by Editorial Team
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Using gas tank sealer is an inexpensive way to fix a leak or crack in your car's gas tank, but the majority of people don't know how to properly apply it. Most gas tank sealers are made from epoxy resin, and there are a number of things that need to be done to make sure that the sealer bonds correctly to the gas tank and completely stops the leak.

Step 1

Drain the gas so that the tank is completely empty, or the fuel level is below the cracked or leaking area. If the leak is coming from the bottom of the tank you will have to drain the gas all the way out. One of the easiest ways to drain the gas is to simply drive your car until the gauge reads empty, but if the leak is too bad this may not be an option.

Step 2

Allow the car to cool down completely and make sure that the gas tank is close to room temperature. You need to let all of the heat dissipate from the exhaust and surrounding components so that you don't get burned or start a fire. If you are in a cold climate you'll need to conduct this repair in a heated garage because the gas tanker sealer won't adhere properly if the tank is too cold.

Step 3

Prepare the gas tank surface for the sealer. Make sure that the area around the crack or leak is completely clean and free of dirt, debris, and gas. Some sealers call for you to sand down the metal or plastic on the tank to allow for a better bond with the sealant, so refer to the specific instructions on your gas tank sealer to see if there are any special requirements about the surface preparation.

Step 4

Thoroughly mix the epoxy and hardener if you are using a two part sealer. One of the biggest mistakes that people make when using an epoxy gas tank sealant is that they don't mix the two chemicals well enough. This results in a weak bond and may not stop your leak properly. Some gas tank sealers do not need to be mixed, so make sure that you take the time to determine which kind you've purchased.

Step 5

Apply an ample amount of sealer over a large area. Using too little sealant can cause the tank to leak again very quickly, and defeat the purpose of your repair. Cover a large area around the site of the leak to make sure that the leak is completely sealed.

Step 6

Give the sealer ample time to dry. In general it's a good idea to wait at least 24-48 hours before driving your car again no matter which brand or type of sealer you are using. If your car is in cold or humid weather you should wait twice as long.

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