FixVault

Radiator Cap Testing

  1. Remove the radiator cap, wet its seal with engine coolant, and then install it on a pressure tester.
    G13142436Courtesy of KIA MOTORS AMERICA, INC.
  2. Apply a pressure of 79.43-122.58 kpa (0.81-1.25 kg/cm2 , 11.52-17.78 psi).
  3. Check for a drop in pressure.
  4. If the pressure drops, replace the cap.


  1. Wait for the engine to cool. Carefully remove the radiator cap and fill the radiator with engine coolant. Then, install it on the pressure tester.
  2. Apply a pressure tester to the radiator and apply a pressure of 79.43-122.58 kpa (0.81-1.25 kg/cm2 , 11.52-17.78 psi).
    G13142437Courtesy of KIA MOTORS AMERICA, INC.
  3. Inspect for engine coolant leaks and a drop in pressure.
  4. Remove the tester and reinstall the radiator cap.
NOTE: Check for engine oil in the coolant and/or coolant in the engine oil.