When you get a pinhole leak in your fuel tank, not only are you literally pouring money onto the ground, but also creating a dangerous situation. Repairing a fuel tank can get difficult, especially when the it is full of fuel. Not to worry, there is a temporary solution to your fuel drip problem: gas tank repair. While the real solution is to replace the fuel tank, that is not always feasible in the short term. Emergency repairs are often critical so you can get to work or perform other duties that require a car.
Keep in mind that we are going to be walking you through repairing small pin hole size leaks in a metal fuel tank. Major damage like gashes from road debris, drilled holes from fuel theft, or major corrosion are not recommended. If you have suffered a major fuel tank leak have the vehicle towed to a repair facility where the tank can be removed and replaced safely.
Gas Tank Repair Options
Fixing pinhole leaks in a fuel tank requires a little prep work and the right products. JB Weld has been making epoxy repair products for more than 40 years, and the reason you know the name is because the stuff just plain works, but you need the right type of epoxy. Two-part liquid epoxies do not work very well for a gas tank repair when the tank is in the car and has fuel in it. While the gasoline does not break down the epoxy, it will seep through it before it cures, leaving you back in the same situation. What you need for a wet repair is JB Weld Autoweld or SteelStik epoxy putty stick.
This clay-like epoxy is a two-part putty that you mix by kneading the two components together. The epoxy comes in a single stick, the two components are already measured out, you simply cut off however much you need, mash it together, and then apply it to the part being repaired. The epoxy hardens after five minutes, and is fully cured in one hour.
Because the epoxy is clay-like consistency, fuel (or other liquids) can’t seep through it or around it. Once cured, the epoxy can withstand 300-degrees and 900 psi of pressure, so it will be perfect for your leaky gas tank. This is the fastest way to keep that expensive fuel in the tank and not on the asphalt.
Fuel Tank Repair Supplies
JB Weld also makes a gas tank repair kit, which consists of a tube of epoxy putty, fiberglass cloth, sandpaper, and an applicator. This repair is the same as the SteelStik, but adds some additional strength with the fiberglass. This is best used in larger repairs or on a tank with multiple pinhole leaks, but it should be limited to cracks shorter than 4″ long and holes smaller than 1/4″ in diameter.
Repairing your tank is easy, you do need a few things before you get started:
- Epoxy putty
- Sandpaper (80-180 grit is fine)
- Absorbent towel (red shop rags are not absorbent enough, use paper or terry cloth)
- Can of brake cleaner or carb cleaner (optional, but a good idea for a better repair)
- Safety glasses
Repairing A Fuel Tank Hole
Safety first so pick a well ventilated area to work as fuel leaks give off potentially dangerous fumes. Ideally work outside for best air flow. If your tank still has fuel in it that is leaking, extinguish any pilot lights or open flames as gas fumes can travel farther than you think.
Begin the repair process by locating the leak. Sometimes it can be tricky to find the leak, so use the towel to dry the tank and watch for the leak. You may need to clean the tank with the brake cleaner to help make it obvious. Once you find the leak, mark it with the pencil.
Put on your safety goggles and clean the area around the leak. You want to clean at least three inches around the damaged area. Use the sandpaper to sand the tank, covering the entire three inch area. Take it down to bare metal. The sanding does two things – cleans any paint, rust, and road grime from the gas tank repair area, as well as gives the epoxy something to grab onto. A rough surface works better than smooth metal. Do not use power tools for sanding the tank as any stray sparks from the sandpaper grit or the electric motor could ignite gas fumes. Hand sanding will do just fine and won’t take very long.
Spray the area with the cleaner and wipe it down. You will likely have to do this several times.
Cut off an amount of epoxy that you think will cover the repair. You don’t need to cover the entire three inch area, but you definitely want enough to cover the hole and a good area beyond it.
Knead the putty to mix the two colors uniformly. The color should be a dark gray.
Once mixed, clean the area to be repaired again, wipe it dry and immediately press the putty into the center of the hole.
Work the putty flat against the tank, ensuring the hole is sealed. You don’t want a big glob on the tank, you want it to be smooth and flat.
The putty should harden in five minutes, and fully cured in one hour. Wait at least an hour to drive the car. We suggest watching the tank for leaks over the next 10-15 minutes, and then check it after the hour has passed. The gas tank should be completely dry around the repair. Your gas tank should now be temporarily repaired and ready to drive. Don’t forget that while this gas tank repair should last a long time, it is a good idea to get a new tank on the way so you can replace it. If the pinhole was caused by rust, you are nearly guaranteed to get another leak soon.
Check out all the JB Weld products available on NAPAOnline or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on gas tank repair, chat with a knowledgeable expert at your local NAPA Auto Parts store.
Photo courtesy of Wikimedia Commons.
A life-long gearhead, Jefferson Bryant spends more time in the shop than anywhere else. His career began in the car audio industry as a shop manager, eventually working his way into a position at Rockford Fosgate as a product designer. In 2003, he began writing tech articles for magazines, and has been working as an automotive journalist ever since. His work has been featured in Car Craft, Hot Rod, Rod & Custom, Truckin’, Mopar Muscle, and many more. Jefferson has also written 4 books and produced countless videos. Jefferson operates Red Dirt Rodz, his personal garage studio, where all of his magazine articles and tech videos are produced.