Thread: Pressure in cooling system when cold

Depends on how much pressure, the system is sealed and was built to keep 1.4 bar constant pressure within managed by the tank cap's pressure valve, the presure would drop a bit when it cools down but there still should be some residual pressure so as long as the top hose is not rock solid IMO there's no problem... it's possible that the cap's valve to be stuck and then the pressure will be higher than required so IMO the first move would be to put a new genuine cap... it must be well tightened to not release pressure near the o-rings cos that will create overpressure due to the microbubbles in the water which are starting above 90*C at ambient temp., that's why it's made to hold 1.4 bar cos at that pressure the boiling point increases to 124*C and no microbubbles untill 115.

Originally Posted by sierrafery

Depends on how much pressure, the system is sealed and was built to keep 1.4 bar constant pressure within managed by the tank cap's pressure valve, the presure would drop a bit when it cools down but there still should be some residual pressure so as long as the top hose is not rock solid IMO there's no problem... it's possible that the cap's valve to be stuck and then the pressure will be higher than required so IMO the first move would be to put a new genuine cap... it must be well tightened to not release pressure near the o-rings cos that will create overpressure due to the microbubbles in the water which are starting above 90*C at ambient temp., that's why it's made to hold 1.4 bar cos at that pressure the boiling point increases to 124*C and no microbubbles untill 115.

Thanks, next time I'll give the top hose a squeeze. If it is rock solid, I'll get a new cap.

Thanks