You may find that it is beneficial to test the cap so that you can be sure that it is working properly.
Radiator cap pressure.
The top portion of the radiator cap will list the pressure rating.
Radiator caps are critical to catch coolant overflow keeping your engine cooling system operating at optimal pressure and temperature and your vehicle operating at optimal performance.
If you have a bad radiator cap the coolant could get released too quickly and cause the reservoir to overflow.
Always use a cap of the correct pressure for your cooling system.
The cap pressure rating has nothing to do with regulating your engine coolant temperature nor will it make your engine run cooler.
If you do not have the equipment to do the radiator cap pressure testing you can have it done at a shop.
The same way a pressure cooker increases the boiling temperature of water.
If there were not a radiator pressure cap installed the system would draw in air.
You have a coolant leak.
When the fluid pressure inside the radiator exceeds 15 psi it forces the valve open allowing heat to escape and excess coolant fluid to overflow into the tanks on either side of the radiator.
Your radiator cap is a small part that plays a big role in keeping your engine from overheating there are several warning signs that your radiator cap is not working right.
While you re in there check to make sure your coolant overflow tank is working properly.
If your coolant is leaking it could mean your radiator cap is bad if the cap isn t releasing excess pressure properly that pressure can force the coolant to leak out at the point of least.
How does this simple cap do this.
You ll notice that there s a plunger on the bottom of the cap.
Air causes poor engine cooling and is the main cause of cooling system component corrosion.
Let s take a pan of water and heat it up.
The cap does this by a spring loaded valve which serves as a pressure relief valve at a rated pressure.
The cap is actually a pressure release valve and on cars it is usually set to 15 psi.
And the boiling point increases 2 3 degrees for each additional psi of pressure in the system.
The boiling point of water increases when the water is.
The radiator cap allows pressure to build up in the cooling system and will eventually vent that pressure to the overflow bottle as the need arises.
The water heats up and boils and 212 degrees.
The radiator cap actually increases the boiling point of your coolant by about 45 f 25 c.
As the vacuum continues to build up the two way check valve which is exactly what a radiator pressure cap is goes to work.
The radiator cap acts as a release valve set to open at the maximum pressure point.
Usually this is set at a density of 15 pounds per square inch psi.
That same mix at 16 pounds per square inch psi of pressure boils at approximately 250 degrees.
We get asked this question daily and it seems most people misunderstand what the pressure cap does.
