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Checking Radiator Cap

Check valve seat (A) of radiator cap.

Fig 1: Identifying Radiator Cap
Courtesy of NISSAN MOTOR CO., U.S.A.
- Check if valve seat is swollen to the extent that the edge of the plunger cannot be seen when watching it vertically from the top.
- Check if valve seat has no soil and damage.
Pull negative-pressure valve to open it, and check that it close completely when released.
- Check that there is no dirt or damage on the valve seat of radiator cap negative-pressure valve.
- Check that there are no unusualness in the opening and closing conditions of negative-pressure valve.
  
  Fig 2: Checking Radiator Cap Valve Operation
  Courtesy of NISSAN MOTOR CO., U.S.A.
Check radiator cap relief pressure.
Standard:

108 - 127 kPa (1.1 - 1.3 kg/cm ² , 16 - 18 psi)

Limit:

88 kPa (0.9 kg/cm ² , 13 psi)
- When connecting radiator cap to the radiator cap tester (commercial service tool) (A) and the radiator cap tester adapter (commercial service tool) (B), apply engine coolant to the cap seal surface.
  
  Fig 3: Checking Radiator Cap Relief Pressure
  Courtesy of NISSAN MOTOR CO., U.S.A.
Replace radiator cap if there is an unusualness related to the above three.

CAUTION: When installing radiator cap, thoroughly wipe out the radiator filler neck to remove any waxy residue or foreign material.