Checking Radiator Cap

WARNING: This page is about a different car, the 2004 Nissan Sentra. However, it is still accessible from the selected car via links, so may be relevant.

Check that there is no dirt or damage on the valve seat of the radiator cap negative-pressure valve.
Check that there are no abnormalities in the opening and closing conditions of the negative-pressure valve.
Pull the negative pressure valve to open it.
Check that it closes completely when released.

Fig 1: Checking Radiator Cap
Courtesy of NISSAN MOTOR CO., U.S.A.
Check radiator cap relief pressure using Tool.
1. Standard :78-98 kPa (0.8-1.0 kg/cm ² , 11-14 psi)
2. Limit :59 kPa (0.6 kg/cm ² , 9 psi)
When connecting the radiator cap to the tester, apply water to the cap seal surface.
Replace the radiator cap if there is an abnormality in the negative-pressure valve, or if the open-valve pressure is outside of the standard values.

Fig 2: Checking Radiator Cap Relief Pressure
Courtesy of NISSAN MOTOR CO., U.S.A.