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Jeep CJ7 Gas Tank

Diagnosing Your Jeep CJ7 Gas Tank Problems

It may seem simple, but the gas tank located between the rear wheels of your CJ7 does more than just storing your fuel. It actually ensures that the gas you fill it with can be measured, vented, and fed to the engine. It also needs to survive a lot of potential damage and prevent sparks from starting as you fill it up. With all of these functions, it's essential that you take care of any problems that arise before they get any worse. Here are a few signs that you need to be aware about:


Jeep CJ7 fuel tanks are made out of steel, and like any other automotive part made out of metal, it can be susceptible to corrode in areas where moisture pools. Make it a point to inspect the interior of your tank, especially under the straps that hold it to your chassis. If you catch the signs of rust in time, you can remove the spots and then fill up any holes with sealing putty. However, if you let your tank corrode, you'll find that you'll be spending a lot on gasoline that just leaks away. You'll need to order up a replacement tank right away.

Blocked or leaking ventilation

Like any vehicle made after 1970, your Jeep CJ7 gas tank has a charcoal canister that filters out pollutants from your fuel system. This canister can sometimes malfunction, and you'll know when this happens thanks to a rough idling experience. You'll need to figure out if the canister has a blockage or if it's got a vacuum leak. Afterwards, you'll know if you should clean out the debris that's blocking the vent or if you should pinch off the vacuum line to take care of the leak.

Fuel contamination

Rough idling can also be an indication of an extremely common problem with tanks: fuel contamination. You'll know that you need to clean out the gas tank when you also experience loss of power, stalling, and premature failures of your other fuel system components.

Pressure build-up

If you experience a sudden surge of vaporized gas hitting your face after you open your gas tank, you can be sure that you've got pressure building up inside. This can be due to movement, heat, or the evaporation of the gas itself. You'll need to reduce the pressure by cooling the tank down so that the gasoline will condense.

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  • Keeping Your Jeep CJ7 Gas Tank Clean

    It's a sad fact of life that gasoline is becoming more and more expensive. To ensure that you don't waste a single drop, you'll need to make sure that the container you store it in is in great shape. Before you do, you need to keep in mind that your Jeep CJ7 gas tank does more than just store your fuel. It actually gauges how much fuel is inside itself, bents off the toxic evaporated gas to be cleaned off, and it sends the gas to the engine when it needs it. Here's how you can ensure that your fuel tank keeps doing all of this in and more:

    Treating the metal gas tank's rust to prevent leaks.

    Remove the tank.

    Many Jeep CJ7 owners find it hard to remove the gas tank from their vehicle. Just keep in mind that you will need to siphon of the fuel inside the tank before you start the removal process. Support the tank from underneath before removing the bolts from along the crossmember, the straps, gas inlet, vent hose, and trim ring. Then you can disconnect the tank from any wires and lines before removing the strapping. After doing all this, you'll be able to lower the tank and removing it from your Jeep.

    Scrape off the rust.

    First, you'll need to use a sharp pick to poke inside any obvious rust spots on your emptied gas tank. Then, expand the hole and remove any surrounding rust. Finally, use sandpaper to remove the surface rust from the exterior of your metal tank. This will ensure that your sealant can stick to the hole properly.

    Seal up any holes.

    Wear rubber gloves and mix up a batch of epoxy in a plastic bucket. Then, apply it to the hole with a paintbrush before placing a fiberglass mesh over it. Apply another layer of epoxy on top and let this dry completely.

    Keeping your gas tank clean.

    Use acetone on your metal tank.

    Remove your fuel tank and make sure that there is no gas inside. Then, use about a pint of acetone to remove any residue. Pour it in and let the tank dry for around 15 minutes. Afterwards, rinse the tank out with water and let it dry completely.

    Clean sugar out of a tank.

    In case someone decides to play a prank on you, you'll need to siphon off the gas into a container. Dispose of this fuel according to the rules in your area. Then, remove your gas tank and fill it with hot water. This will dissolve the sugar in about two hours, so let it sit inside the tank for a while. Afterwards, pour the water out and dry the tank with a hair dryer. Replace the components that have been destroyed by the sugar before returning the tank to your Jeep CJ7.