GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 24460-01 Cooling System and Cap Pressure Tester

Radiator Cap Pressure Test

    Caution: As long as there is pressure in the cooling system, the temperature can be considerably higher than the boiling temperature of the solution in the radiator without causing the solution to boil. Removal of the pressure cap while the engine is hot and pressure is high will cause the solution to boil instantaneously -- possibly with explosive force -- spewing the solution over the engine, fenders and the person removing the cap.

  1. Remove the radiator cap.
  2. Wet the radiator cap gasket with water. Wash off any sediment from the sealing surface.

  3. Object Number: 1375  Size: SH
  4. Install the cap to J 24460-01 .
  5. Pump up the pressure to 103 kPa (15 psi) by operating the plunger handle of J 24460-01 .
  6. Note the rate of decrease in pressure.
  7. The pressure reading should remain within the corresponding pressure segment of the scale for about 10 seconds.
  8. If the cap does not hold the corresponding pressure, replace the cap.