What is the purpose of a radiator cap in a vehicle?

The purpose of a radiator cap is to pressurize the cooling system, which effectively raises the boiling point of the coolant. By creating a sealed environment within the cooling system, the radiator cap allows for increased pressure, which prevents the coolant from boiling at its normal temperature. This is crucial for the efficient operation of the engine, as it enables the cooling system to operate under higher temperatures without causing boiling, thus ensuring that the engine remains effectively cooled.

The increased boiling point allows the engine to run at higher temperatures, improving efficiency and performance while also helping to prevent overheating. This function is vital because if the coolant were to boil, it could lead to a loss of coolant and serious engine damage. The design of the radiator cap typically includes a spring-loaded mechanism that helps maintain the proper pressure within the system, releasing excess pressure as needed to prevent damage.

While measuring coolant levels, providing outlets for steam, or connecting hoses are relevant functions in the cooling system, they are not the primary purpose of the radiator cap itself. Its vital role in pressurization fundamentally supports the overall cooling system's functionality and reliability.