Wait until the engine is cool, then carefully remove the radiator cap (A). Wet the radiator cap seal with engine coolant, then install it on a commercially available pressure tester (B).

Apply a pressure of 93?123 kPa (0.95?1.25 kgf/cm², 13.5?17.8 psi).

Check for a drop in pressure.

If the pressure drops, replace the radiator cap.