GM Service Manual Online
For 1990-2009 cars only

Testing Procedure (On Vehicle)

Notice: Do not use pressure greater than 138 kPa (20 psi) to test the radiator. Damage to the radiator will result if a higher pressure is used.

Tools Required

    • J 24460-01 Cooling System and Cap Pressure Tester
  1. After the system has cooled, remove the radiator/surge tank pressure cap.

  2. Object Number: 11658  Size: SH
  3. Connect the J 24460-01 to the radiator.
  4. Apply normal system operating pressure. Do not exceed 138 kPa (20 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 or repair as required.
  7. In order to ensure the cap maintains the correct pressure, check the radiator/surge tank cap using the J 24460-01 .
  8. If the radiator leaks during the pressure test, mark the leak area so the leak is found once the radiator has been removed from the vehicle.

Testing Procedure (Off Vehicle)

Tools Required

J 24460-01 Cooling System and Cap Pressure Tester


    Object Number: 3339  Size: SH

    Notice: Do not use boil-out tanks that have been used for copper or brass radiators. The flux and caustic cleaners remaining in these tanks will attack the aluminum radiator causing failure. Use a separate tank containing clean water for servicing aluminum and plastic radiators.

  1. Install test fittings, or rubber test caps, in the inlet and outlet necks. Seal the oil cooler fittings with metal plugs in order to protect the cooler and to keep fluid from running out.

  2. Object Number: 11658  Size: SH
  3. Attach the J 24460-01 to the radiator.
  4. Gradually apply normal system pressure until 138 kPa (20 psi) is reached. Do not exceed 138 kPa (20 psi).
  5. Check the pressure gauge to see if there is pressure loss.
  6. In order to make sure that there are no small leaks, run water over the suspect area. Look for any bubbles. Using a mild detergent is helpful.
  7. If a large water tank is available, you can submerge the radiator. Then, check for air bubbles.