Pressure in cooling system.
 

I understand that when the car is hot there should be pressure in the cooling system and hence the air would come out when opening the coolant valve. My question is whether the system is always under pressure.? I try letting the car idle for two weeks and the systen is still pressurelized.

If the system always have pressure does this mean as long as the system is presiirelized there would be no leak?

2001 S Tip with 100K KM

Thx

When the car is cold there is no pressure. That's why you can open the coolant cap and nothing happens or comes out.

When the system is hot and becomes under pressure, that's mostly when you will experience any leaks.

Any idea how long should I let the car cool down before the pressure is gone? I try two weeks but the system is still pressurised.

Sorry, but that's impossible....

there may be a tiny bit of residual pressure, enough to sound like a release of air, but it should not be pressurized to the point that coolant wants to shoot out of the cap.

.....yep, to what Quadcammer said!