The radiator cap is a critical component of your engine’s cooling system as it has the twin responsibilities of storing coolant and ensuring the necessary pressure of the cooling system is maintained.
The pressure inside the radiator is sixteen pounds psi (per square inch). The radiator cap is designed to ensure that this pressure is always maintained to prevent overheating. If your car overheats, the radiator can sustain damage. This can have a cascading effect on other components of the cooling system and the engine.