Cooling System Leak Testing

Special Tools

• J-24460-A  Radiator Pressure Tester
• J-42401-A  Radiator Cap and Surge Tank Test Adapter

For equivalent regional tools, refer to Special Tools .

1. Remove the pressure cap.
   WARNING: 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.
   WARNING: 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.
2. Wash the pressure cap mating surface with water.
3. Test the operation of the pressure cap. Refer to Pressure Cap Testing .
4. Install the J-42401-2  pressure test adapter (1) to the coolant recovery reservoir (2) to plug the reservoir bleeder gallery.
   Fig 1: J-42401-2 Pressure Test Adapter And Coolant Recovery Reservoir

   Courtesy of GENERAL MOTORS COMPANY
5. Install the J-42401-3  adapter to the coolant recovery reservoir.
6. Install the J-24460-A  pressure tester to the J-42401-3  adapter.
7. Using the pressure tester apply pressure to the cooling system.
   NOTE: Do NOT exceed the pressure cap rating.
8. Observe the gage of the pressure tester for any loss.
9. The cooling system should hold the rated pressure for at least 2 minutes.
10. Repair any leaks as required.