[Sealevel]

I've also been running the MINI in some brutal heat lately and like BruceK's it stays in the middle, so something's amiss with yours. Could be any of several problems if the coolant level's okay--fan clutch, thermostat, water pump. Two things you can check on your own: Make sure the radiator cap/expansion tank cap is on tight as the cooling system has to be at its designed pressure to work effectively--check this on a cold engine, fiddling with the cap on a hot engine can cause an overflow that will burn your hand. (Do Coopers have a radiator cap?--can't tell with my S, the supercharger blocks the view). And especially if you've had your MINI a while and have been out killing hoards of bugs, open your hood (bonnet) and hose the mess off the front of your radiator/ac evaporator.