GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1996 🢒 DeVille 🢒 Engine 🢒 Engine Controls - 4.0L and 4.6L 🢒 Fuel Tank Leak Check

Notice: 

   • Before attempting the Fuel Tank Leak Check, place a dry chemical (Class B) fire extinguisher near work area.
   • Before removing the fuel tank for a suspected leak, make sure the fuel pipes are not leaking onto the fuel tank. Once the fuel tank is removed, make sure fuel is not leaking around the fuel sender assembly O-ring.
   • This check requires a fuel sender assembly and an O-ring to be installed in the fuel tank.

  1. Relieve fuel system pressure. Refer to Fuel Pressure Relief Procedure .
  2. Drain fuel tank. Refer to Fuel Tank Replacement (Draining) .
  3. Remove fuel tank. Refer to Fuel Tank Replacement .
  4. Plug all outlets as follows:
    5. • Connect a piece of hose to the filler pipe nipple and plug opposite end.
    • Install fuel lever sender with new seal and plug fuel feed pipe and return pipe.
    • Connect a piece of hose to the tank vent valve and plug opposite end.
  5. Connect a piece of hose to the vent pipe nipple.
  6. Submerge tank in water or apply soap solution to outside of tank.
  7. Apply 7 to 10 kPa (1 to 1 1/2 psi) air pressure to the hose on the fuel tank vent pipe nipple.

    8. Air bubbles appearing from fuel tank indicate a leak. Replace fuel tank if it is leaking. Refer to Fuel Tank Replacement .