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Home >> Subaru >> 2016 >> WRX Base >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 8 (Engine Cooling System (WRX-STI)) >> Radiator Cap >> Inspection

Radiator Cap: Inspection

WARNING: This page is about a different variant/trim than selected.
  1. Check that the radiator cap does not have deformation, cracks or damage.
  2. Attach the radiator cap tester to radiator cap.
    Fig 1: Attaching Radiator Cap Tester To Radiator Cap
    G07909908Courtesy of SUBARU OF AMERICA, INC.
  3. Increase pressure until the radiator cap tester gauge needle stops. Radiator cap is functioning properly if it holds the service limit pressure for 5 - 6 seconds. Replace the radiator cap if its valve opens at less than the service limit.

    Coolant filler tank side: 

    Standard 

    93 - 123 kPa (0.95 - 1.25 kg/cm 2  , 14 - 18 psi) 

    Limit 

    83 kPa (0.85 kg/cm 2  , 12 psi) 

    Radiator side: 

    Standard 

    122 - 152 kPa (1.24 - 1.55 kg/cm 2  , 18 - 22 psi) 

    Limit 

    112 kPa (1.14 kg/cm 2  , 16 psi) 

    CAUTION:
    • Be sure to remove foreign matter and rust from the cap in advance. Otherwise, results of pressure test will be incorrect.
    • Do not confuse the cap of coolant filler tank and cap of radiator.