Pressure Cap Testing

Tools Required 

• J 24460-01  Cooling System Pressure Tester
• J 42401  Radiator Cap/Surge Tank Test Adapter
  CAUTION: To avoid being burned, do not remove the radiator cap or surge tank cap while the engine is hot. The cooling system will release scalding fluid and steam under pressure if radiator cap or surge tank cap is removed while the engine and radiator are still hot.

1. Remove the pressure cap.
2. Wash the pressure cap sealing surface with water.
3. Use J 24460-01  and J 42401  in order to test the pressure cap for the following conditions:
   • Pressure release when J 24460-01  exceeds the pressure rating of the pressure cap.
   • Maintain the rated pressure for at least 10 seconds.

     Note the rate of pressure loss.

Fig 1: Identifying J 24460-01
Courtesy of GENERAL MOTORS CORP.
4. Replace the pressure cap if either of the following conditions is true:
   • The pressure cap does not release pressure which exceeds the rated pressure of the cap.
   • The pressure cap does not hold the rated pressure.