No Pressure Behind Radiator Cap

Let s take a pan of water and heat it up.

No pressure behind radiator cap. Kind of like the pressure or noise that is created after the car runs and you take off the radiator fill cap although that is air pushing out. As long as there is enough coolant there is no room for air. When the vehicle is fully warmed up the coolant is boiling hot and under pressure. Thanks also toolmanmike yes i test my cap already first i think the lower rubber on the spring not long enough to touch the surface of the radiator opening and seals my radiator only with the top rubber and this means i have all the time a open connection between my radiator itself and my overflow tank where is also not seal because he have a overflow on it without any pressure opening.

Sometimes its hard to find a correct radiator cap. As the vacuum continues to build up the two way check valve which is exactly what a radiator pressure cap is goes to work. In the case of my gas tank it is air sucking in as if the tank is pressurized. The water heats up and boils and 212 degrees.

Pressure testing the radiator. Do not remove the recovery tank cap or radiator cap before the engine has adequately cooled. But lately there is virtually no pressure or air suck noise when i take off the cap. The cap allows the liquid that was transferred from the radiator to the external reservoir to be pulled back.

Cost was only 3 or 4 dollars. If you have a radiator pressure tester then you can inspect the cooling system on your own. The old mopars originally had no pressure radiator systems. The cap pressure rating has nothing to do with regulating your engine coolant temperature nor will it make your engine run cooler.

Visually inspect that cap to make sure the spring moves freely and there is no debris or corrosion under the cap.