GM Service Manual Online
For 1990-2009 cars only

Special Tools

    • J-42401 Radiator Cap and Surge Tank Test Adapter
    • J-24460-01 Cooling System Pressure Tester

    Warning: To avoid being burned, do not remove the radiator cap or surge tank cap while the engine is hot. The cooling system will release scalding fluid and steam under pressure if radiator cap or surge tank cap is removed while the engine and radiator are still hot.

  1. Remove the pressure cap.
  2. Wash the pressure cap sealing surface with water.

  3. Object Number: 1375  Size: SH

    Note: Lubricate J-42401 adapter and pressure cap O-rings with coolant and press cap to seat O-ring on J-42401 adapter before turning to engage threads.

  4. Use the J-24460-01 tester in order to test the pressure cap.
  5. Test the pressure cap for the following conditions:
  6. • Pressure release when the J-24460-01 tester exceeds the pressure rating of the pressure cap.
    • Maintain the rated pressure for at least 10 seconds.
  7. Replace the pressure cap under the following conditions:
  8. • The pressure cap does not release pressure which exceeds the rated pressure of the cap.
    • The pressure cap does not hold the rated pressure.