How to Fix a Truck's Leaking Gas Tank

by Keith Stringer
pick up image by thierry burot from

Leaking fuel tanks are a hazard to the environment, yourself and other drivers. Leaking fuel tanks should be fixed as soon as possible to avoid a dangerous accident and higher-than-normal fuel consumption. Fixing a tank at home can be completed in a day if you are familiar with the instructions and have all the tools and products available. To ensure proper sealing of all tanks, you should treat the exterior and interior of the tank.

Removing The Tank

Step 1

Position the car jacks under the vehicle. Ensure that you are jacking the vehicle from a jacking point directly connected to the vehicle's frame.

Step 2

Jack the car up and replace the jack with a stand one side at a time. For some low vehicles, you may have to jack the front as well as rear to access the tank. But for most vehicles only jacking the rear of the vehicle will be sufficient for tank removal.

Step 3

Loosen slowly the bolts that hold the fuel tank to the vehicle. There may be steel straps that run from bolt to bolt securing the tank.

Step 4

Disconnect electrical and fuel lines with a tool set. The electrical contactors are usually attached to the fuel pump with quick disconnect clips, but in some cases you will have to disconnect the wires by loosening the tension screws located on the fuel pump.

Step 5

Lower the tank to the ground and slowly pull it from under the vehicle once it is free from vehicle.

Drain any remaining fuel from tank into plastic gas cans by slowly turning the tank over on its side toward the main access point. A funnel is usually needed to ensure that no gas is spilled.

Preparing Tank for Sealer

Step 1

Clean the entire fuel tank with degreaser. This will help you to identify any problem areas and also help the putty seal the tank.

Step 2

Sand or file any rust spots or such problem areas as visible cracking, holes or areas that feel soft to the touch.

Step 3

Fill problem areas with fuel tank putty, which should be applied just as any other putty by using a putty knife. Place a generous amount of putty in a problem area and work the putty smooth with the knife.

Step 4

Allow the putty to dry and repeat the process if needed until all problem areas are prepared.

Spray metal primer over the repaired areas once the putty is dry. The putty container should state the drying time needed.

Sealing Tank With Epoxy

Step 1

Mix two-part epoxy fuel tank sealer as directed on the product label.

Step 2

Pour the entire mixture into the tank. This will put between one to three quarts of mixture, enough to allow the mixture to coat the entire tank. Allow the mixture to flow freely in the tank.

Step 3

Tape all open access points on the tank to prevent any sealer mixture from escaping.

Step 4

Slosh the sealer mixture in the fuel tank, ensuring that all sides and the top of tank have been coated with sealer. Turn the tank over multiple times during this step.

Wait five minutes and repeat the process of sloshing the sealer mixture in the tank. This will ensure proper coverage. You are painting the inside of the tank with the sealer mixture just as you would a room with a paint brush, but in this case the extra sealing mixture in the tank is coating the inside of the tank.

Draining Sealer Muxture

Step 1

Remove the masking tape from the main access points that you taped over before pouring the sealer mixture into the fuel tank.

Step 2

Pour the remaining sealer mixture into a bucket lined with a trash bag to prevent a mess. The mixture will harden and should be properly disposed.

Step 3

Allow the sealer to dry overnight before reinstalling the tank on your vehicle.

Reinstall the tank on your vehicle and fill it with gasoline. Remember to re-attach all wires and hoses that you removed during the tank's removal.


  • As a test, fill fuel tank up before re-installation to ensure that the leak has been properly sealed.


  • Do not rush the cure time of the sealer. Most sealers will cure overnight, but to be sure to consult the manufacture's directions for the proper sealing time.

Items you will need

  • Automotive jacks/stands
  • Mechanics tool set
  • Plastic gas tank
  • Metal primer
  • Sand paper/file
  • Degreaser
  • Fuel tank putty
  • Fuel tank epoxy sealer
  • Masking tape

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