What Is Radiator Cap Function?

Radiator cap function is very big,although the size of it is very small.One of the most important auto part is radiator cap in cooling system.


Radiator cap has 5 parts.They are outer cover,upper seal,lower seal,vacuum valve and pressure spring.Please check below picture.


The knowledge of radiator cap could help us to know radiator cap function more clearly.Below are some radiator cap function.


Obviously, one of the functions of the radiator cap is to prevent the coolant in the radiator from pouring out.


In addition to preventing the radiator’s coolant from pouring out, the radiator cap keeps the cooling system under pressure, raising the boiling point. From the 1950s onwards, most cooling systems are pressurized. In a closed cooling system, the boiling point rises three degrees for every pound of pressure.


When the coolant heats up, it expands, or increases in volume, creating more pressure in the cooling system.If cooling system reach the pressure of radiator cap,pressure spring will compress.It will allow coolant flow into fluid reservoir.In this process,coolant will be expand.And it could keep cooling system in the suitable work pressure.


Radiator cap has vacuum valve.When cooling,vacuum valve could allow coolant flow into fluid reservoir.When coolant temperature descend,coolant will shrink and be vacuum.At this moment,vacuum valve valve will open.Coolant will flow into radiator.It could help it to be normal pressure.


Also, the role of the radiator cap is to seal the cooling system and prevent any air from entering the system. Air is enemy number one of any cooling system. The air in the cooling system cannot maintain the proper operating temperature. Air in the system can cause overheating.


It can be seen that the radiator cap is a very important cooling system accessory that is easily overlooked, cheap, but not to be lost.