GM Service Manual Online
For 1990-2009 cars only

Special Tools

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

    Caution: In order to help avoid being burned, do not remove the radiator cap while the engine and the radiator are hot. Scalding fluid and steam can be blown out under pressure if the cap is removed too soon.

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

  3. Object Number: 850101  Size: SH

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

  4. Use J 24460-01 (1) with J 42401 (2) in order to test the radiator cap.
  5. Test the pressure cap for the following conditions:
  6. • Pressure the release when J 24460-01 exceeds the pressure rating of the pressure cap.
    • Maintain the rated pressure for at least 10 seconds.
    • Note the rate of pressure loss.
  7. Replace the pressure cap under the following conditions:
  8. • The pressure cap does not release the pressure which exceeds the rated pressure of the cap.
    • The pressure cap does not hold the rated pressure.