GM Service Manual Online
For 1990-2009 cars only

Leak Testing Procedure (On Vehicle)

Tools Required

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.

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

  2. Object Number: 11658  Size: SH
  3. Connect the cooling system tester J 24460-01 to the radiator/surge tank.
  4. Apply normal system operating pressure. Do not exceed 138 kPa (20 psi).

  5. Object Number: 1374  Size: SH
  6. 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.
  7. Tighten the hose connections or repair as required.

  8. Object Number: 1375  Size: SH
  9. Check the radiator/surge tank cap with J 24460-01 in order to ensure the cap maintains the correct pressure.
  10. If the radiator leaks during the pressure test, mark the leak area so the leak can be located once the radiator has been removed from the vehicle.

Testing Procedure (Off Vehicle)

Tools Required

J 24460-01 Cooling System and Cap Pressure Tester

    Notice: Do not use boil-out tanks or any other tank that has been used for copper or brass radiators. The remaining solutions or chemicals in these tanks could cause radiator failure.

  1. Plug the inlet and outlet tubes. Make sure the drain cock is closed.
  2. Attach the J 24460-01 to the radiator.
  3. Apply pressure to the radiator. Do not exceed 138 kPa (20 psi) of pressure.
  4. Observe the gauge for any pressure loss.
  5. Run water over the repair area and look for any bubbles. If a large tank is available, the radiator can be submerged in order to check for air bubbles.