GM Service Manual Online
For 1990-2009 cars only

Leak Testing Procedure (On Vehicle)

Tools Required

    • J 24460-01 Cooling System Tester
    • J 42070 Cooling System Adapter Set

    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.

  1. After the system has cooled, remove the surge tank pressure cap.

  2. Object Number: 141909  Size: MH
  3. Connect the cooling system tester, J 24460-01 , and the adapter, J 42070 , to the surge tank.
  4. Apply normal system operating pressure. Do not exceed 100 kPa (14.5 psi).
  5. Watch the gauge needle for an indication of a leak. Examine all cooling system connections and components, including the radiator and the heater core, for leaking coolant.
  6. Tighten the hose connections and/or repair as required.

  7. Object Number: 141919  Size: SH
  8. Check the surge tank cap with J 24460-01 and J 42070 in order to ensure the cap maintains the correct pressure.
  9. Slowly apply pressure. If the surge tank cap fails to hold 100 kPa (14.5 psi), replace the surge tank cap.