CSF Radiator Pressure Cap

When pressures inside your cooling system increase above its psi rating, the radiator pressure cap release some of the coolants into the overflow tank. It does this by use of a spring loaded valve. Once enough coolant has exited the system to reduce the pressure, the valve closes again. This action allows the system to remain at the optimal psi while the engine is running.

When the engine cools and pressure in the system drops, the radiator pressure cap allows the excess coolant in the overflow tank to return to the system by use of a second spring loaded valve. This second valve responds to the vacuum created in the system from the drop in pressure and pulls the coolant out of the overflow tank. Not only does this recycle the excess coolant to prevent air pockets in the radiator, but it also prevents the softer components of the cooling system, such as the hoses, from becoming crushed by the external air pressure.