GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 24460-01 Cooling System Tester

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 radiator cap.
  2. Wet the radiator cap gasket with water. Wash off any sediment from the sealing surface.
  3. Install the cap to J 24460-01 .
  4. Pump up the pressure to the pressure stamped on the cap by operating the plunger handle of J 24460-01 .
  5. Note the rate of decrease in pressure.
  6. The pressure reading should remain within the corresponding pressure segment of the scale for about 10 seconds.
  7. If the cap does not hold the corresponding pressure, replace the cap.