Radiator Cap Testing

Remove the radiator cap, wet its seal with engine coolant, and then install it on a pressure tester.

Fig 1: Applying Pressure On Radiator Cap
Courtesy of HYUNDAI MOTOR AMERICA
Apply a pressure of 93 ~ 123 kPa (0.95 ~ 1.25 kg/cm² , 14 ~ 19 psi).
Check for a drop in pressure.
If the pressure drops, replace the cap.