GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 24460-01 Cooling System Pressure Tester
    •  J 46143 Cooling System Adapter

    Caution: To avoid being burned, do not remove the starter/generator control module (SGCM) cap while the SGCM is hot. The cooling system will release scalding fluid and steam under pressure if the SGCM cap is removed while the SGCM is still hot.


    Object Number: 1206674  Size: SH
  1. Follow the steps below in order to remove the starter/generator control module (SGCM) coolant tank cap.
  2. 1.1. Slowly rotate the cap counterclockwise.
    1.2. Stop rotating and allow the hissing to stop.
    1.3. After all the hissing stops, continue turning counterclockwise in order to remove the cap.
  3. Wash the pressure cap sealing surface with water.

  4. Object Number: 850101  Size: SH
  5. Use the J 24460-01  (1) with the J 46143 in order to test the pressure cap.
  6. Test the pressure cap for the following conditions:
  7. • Pressure release when the 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.
  8. Replace the pressure cap under the following conditions:
  9. • The pressure cap does not release pressure which exceeds the rated pressure of the cap.
    • The pressure cap does not hold the rated pressure.