2002 Buick Rendezvous - Coolant Recovery Tank And Radiator Cap

Why Does My Car Need A Radiator Cap?

Your radiator cap, or coolant recovery tank cap, seals the opening used to add or test coolant and controls the pressure inside your cooling system. The vehicle you drive will determine whether the cap is located on the radiator or the coolant recovery or overflow tank, but both designs serve the same purpose. When the pressure inside the cooling system is too high, the radiator cap's spring-loaded sealing surface opens slightly and vents excess coolant to the coolant reservoir. Once the pressure has been restored to appropriate levels, the radiator cap restores the seal to prevent coolant loss. If your radiator cap isn't venting, this can cause excessive pressure to build in the cooling system. High cooling system pressure can cause leaks or result in a collapsed radiator hose, which can prevent coolant from moving throughout the system and lead to overheating. A radiator cap that is no longer sealing could also leak, and this will prevent the appropriate pressure from being maintained in the cooling system. At operating temperature, coolant can evaporate from the system if the proper pressure levels are not maintained, and coolant leaks, evaporation, or obstacles in the system can quickly cause overheating and engine damage. It is a good idea to add inspection of your radiator cap or coolant recovery tank cap to your routine maintenance checklist, and to check your radiator cap for signs of wear if it appears to be leaking or if the cooling system is not working as it should. If you need a replacement radiator cap or coolant reservoir cap, shop O'Reilly Auto Parts for the right cooling system parts for your application.