GM Service Manual Online
For 1990-2009 cars only

Radiator Fill Cap Inspection

    • Check the cap for a weak spring washer or damage to the gasket. If the spring washer is weak, replace the cap.
    • Check the relief valve gasket in the cap and the inner sealing surface of the fill neck for damage or debris.
    • Check for cracks at the hose fitting on the fill neck. If the fitting is loose or cracked, replace the radiator end tank.

Radiator Cap Pressure Testing Procedure

Tools Required

J 24460-01 Cooling System Pressure Tester

  1. Clean the cap.

  2. Object Number: 1375  Size: SH
  3. Install the cap on the J 24460-01 .
  4. In order to obtain the minimum holding pressure, slowly pump the J 24460-01 .
  5. • If the cap fails to hold 83 kPa (12 psi) of pressure, replace the cap.
    • If a new cap is installed, coat both gaskets with engine coolant.