GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 24460-01 EN-48501 Pressure Cap Adapter
    • J 24460-01 J-48501 Radiator Cap Pressure Adapter
    • J 24460-01 J-24460-01 Cooling System and Cap Pressure Tester

Caution: Under pressure, the temperature of the solution in the radiator can be considerably higher, without boiling. Removing the radiator cap while the engine is hot (pressure is high), will cause the solution to boil instantaneously, with explosive force. The solution will spew out over the engine, fenders, and the person removing the cap. Serious bodily injury may result. Flammable antifreeze, such as alcohol, is not recommended for use at any time. Flammable antifreeze could cause a serious fire.

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.

Caution: Refer to Radiator Cap Removal Caution in the Preface section.

Caution: Refer to Safety Glasses Caution in the Preface section.

Ensure engine is below 50 C before removing the coolant pressure cap.


Object Number: 1949744  Size: SH

Caution: Refer to General Repair Instructions in the Preface section.

Inspect and clean the sealing O-rings (1) with a wet cloth.


    Object Number: 1949741  Size: SH
  1. Attach the coolant filler cap (1) to a commercially available cooling system pressure tester (2), using the pressure cap adapter (4) and the pressure tester adapter (3).
  2. Notice: Refer to General Repair Instructions in the Preface section.

  3. Slowly pressurise cap to 120 - 150 kPa (17 - 22 psi).
  4. Notice: Refer to General Repair Instructions in the Preface section.


    Object Number: 1949743  Size: SH
  5. Prior to installing the coolant pressure cap ensure that the coolant filler neck cap seating surface (1) is clean and free from obstruction.
  6. Notice: Refer to Fastener Notice in the Preface section.

  7. Install the coolant pressure cap.
  8. Tighten
    Tighten the cap to 3.0 Nm (27 lb in).