Radiator Cap: Service and Repair
INSPECTION
Hold the cap in your hand, right side up The vent valve at the bottom of the cap should fall open. Turn the cap upside down. The vent valve should close.
Replace the cap for any of the following conditions:
- Rubber gasket has swollen, preventing the valve from opening
- Any light can be seen between the vent valve and the rubber gasket (with cap upside down)
- Gasket on the bottom of the cap shows noticeable thinning
- Cap has been through more than one engine overheat.