water pressure relief valve

[jyjolly]

How important and what is the function of this valve. Could a faulty one make your engine overheat also when open where does the water go. Thanks

[Joe Reeves]

In order for that valve to cause a overheating problem, it would need to be frozen shut.

Without that valve, the engine would run too cold.

It's purpose is to open under pressure when the thermostat is still closed.

[jyjolly]

Relief valve

Thanks Joe makes sense now.