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Cooling System Cap Inspection

WARNING: This page is about a different car, the 2003 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.
WARNING:
  • Never remove the cooling system cap while the engine is running, or when the engine and radiator are hot. Scalding coolant and steam may shoot out and cause serious injury. It may also damage the engine and cooling system.
  • Turn off the engine and wait until it is cool. Even then, be very careful when removing the cap. Wrap a thick cloth around it and slowly turn it counterclockwise to the first stop. Step back while the pressure escapes.
  • When you're sure all the pressure is gone, press down on the cap using the cloth, turn it, and remove it.
  1. Clean the cooling system cap and the sealed part.
  2. Inspect the crack or turn over on the sealed part of the cooling system cap.
    • If not as specified, replace the cooling system cap.
  3. Fill the SST  (L3 engine model), commercially available radiator cap tester (AJ engine model) with the water or the engine coolant to the full level and attach the cooling system cap to the SST  (L3 engine model), radiator cap tester (AJ engine model).
  4. Hold the cooling system cap downward and apply pressure gradually. Verify that the pressure become held for 10 s  within the specification.
    • If the pressure is not held stable within the specification, replace the cooling system cap.
    Fig 1: Testing Cooling System Cap
    G01929764Courtesy of MAZDA MOTORS CORP.

    Pressure 

    1. L3:113-142 kPa {1.15-1.44 kgf/cm 2  , 16.4-20.4 psi} 
    2. AJ: 94-122 kPa {0.95-1.25 kgf/cm 2  , 13.6-17.7 psi}