GM Service Manual Online
For 1990-2009 cars only

Caution: Place a dry chemical (Class B) fire extinguisher near the area before performing a Fuel Tank Leak Check. Before removing the fuel tank for a suspected leak, make sure that the fuel pipes or the tubes are not leaking onto the tank. Once removed, make sure that the fuel is not leaking around the fuel sender O-ring. Failure to follow these precautions may result in personal injury.

Important: This check requires a fuel sender assembly, a fuel filler cap, and a fuel sender gasket to be installed in the fuel tank.

  1. Relieve fuel system pressure. Refer to Fuel Pressure Relief .
  2. Remove the fuel tank. Refer to Fuel Tank Pressure Sensor Replacement .
  3. Cap the fuel feed pipe, the fuel return pipe, and the EVAP pipe on the fuel sender assembly.
  4. Install a piece of fuel line on vent pipe.
  5. Submerge the fuel tank in water or apply a soap solution to the outside of the fuel tank.
  6. Apply 31-38 kPa (4½-5½ psi) air pressure to the piece of hose on the fuel tank vent pipe. Air bubbles appearing from the fuel tank indicate a leak.
  7. Replace the fuel tank if it is leaking. Refer to Fuel Tank Pressure Sensor Replacement .