Yeah, I understand that... but you need to consider the pressure cap is there to increase the boiling point of the coolant.Quote:
Originally Posted by JackCollo
If the pressure cap is knackered the coolant boils at a lower temp
It is OK while driving as the coolant circulates so is constantly getting colder coolant from the Rad
If the pressure is low then when you stop the coolant now 'trapped' in the engine boils and blows by.
Your symptoms are very indicative of a dodgy cap.
It may turn out to be something else but as prev mentioned do the easy/cheap things first
If it is blocked Rad fins etc then the issue tends to be overheating when under load not after being turned off
