Radiator Cap Testing

WARNING: This page is about a different car, the 2014 Kia Forte. However, it is still accessible from the selected car via links, so may be relevant.

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

Fig 1: Testing Radiator Cap By Applying Pressure
Courtesy of KIA MOTORS AMERICA, INC.
Apply a pressure of 93.16 ~ 122.58 kPa (0.95 ~ 1.25 kgf/cm² , 13.51 ~ 17.78 psi).
Check for a drop in pressure.
If the pressure drops, replace the cap.