Mini Cooper Forum banner
1 - 4 of 4 Posts

·
Registered
Joined
·
478 Posts
And ? i don't inderstand.

I opened the water tank and the water was not boiling.
There was even pressure on the water tank cap.
The water doesn't boil at 108C because the coolant system is under pressure. The higher the pressure the higher the temperature can be without the water boiling. The expansion tank water will be at the same pressure as the rest of the coolant system, but it will be cooler because it does not form part of the circulation system, so I am not surprised it wasn't boiling.

Opening the cap can be dangerous, so be careful. If the engine was really hot you would be hard pushed to keep the pressure under control as the cap is released, and this can also be followed with steam and hot water.

108C is about right for normal running temperature.

I guess there is nothing wrong, but the dealer will be able to test the temperature with a IR thermometer to check it
 

·
Registered
Joined
·
478 Posts
Is it the fan running or the electric cooling pump? From a quick look at the parts diagrams the Cooper S has an electric and mechanical water pump, also the turbo is water cooled, so its possible you are hearing the electric water pump taking the heat out of the turbo when the engine is switched off.
 

·
Registered
Joined
·
478 Posts
Was that noise just fan or was the engine running? I agree ambient temperature or -7C plus wind chill should see a car struggle to gain temperature, not lose it. So if it was my car I would do a little investigation. I guess there could be a problem with the engine thermostat, if that stuck closed then the radiator would not come into play to cool the engine.

Looking at the cooling circuit diagram if the radiator hose top right (as you look at the car) is not hot (very hot) when the fan is running, there is a problem. If its just warm then I bet the thermostat is stuck, or the system has an air lock, either way it's a dealer job.

BE VERY CAREFUL. IT WILL BE HOT AND THE FAN WILL BE SPINNING. (You don't want to put your fingers in a spinning fan)

If the thermostat is stuck closed it's not a problem this time of year, the heater will have taken the heat out of the engine, and air flow around the engine would have kept it cool, but as the temperature warms up it will no longer be enough and the engine will start to overheat. A stuck stat will explain why when you removed coolant cap there was no real heat in the expansion tank.
 
1 - 4 of 4 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top