Thinking about purchasing a new car? Use our new Car Loan Calculator to estimate your monthly car payment!

How to Pressure Test a Gas Tank

by Alissa Jordan

Fuel problems can be difficult to diagnose without paying the host costs of a repair shop. Pressure testing is an excellent, inexpensive way to troubleshoot problems with gas tanks and fuel pump systems. By pressure testing, you can rule out certain conditions, such as a leak in the tank or a plugged outlet. This quick method demonstrates pressure testing while the tank is still inside the car, reducing labor costs.

Locate the supply and return lines running out of the tank reservoir. Clamp the supply line tightly with a pair of needle nose vise grips. Clamp return line tightly with a pair needle nose vice grips.

Find the overflow house next to the fill spout and clamp with the remaining pair of needle nose vise grips.

Place a rubber grommet of correct size into fill spout, pushing hard to ensure a complete seal. Pump pressure tester up to 10 pounds per square inch (psi). Do not exceed 12 psi. Let it stand for five minutes.

Check the pressure tester gauge for the psi readout. If the pressure has dropped from the original reading, there is a leak. If pressure has held, the tank is leak-free.


  • Do not exceed 12 psi when pressure testing the gas tank.

Items you will need

About the Author

This article was written by the It Still Runs team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information. To submit your questions or ideas, or to simply learn more about It Still Runs, contact us.

More Articles

Photo Credits