[quenching]

Hi there,

You guys are always very helpful so maybe you can help here. I have an 04 Cooper S with 35k miles on it, 8k left to service. The other day after driving for about an hour in city traffic the temperature gauge suddenly rose from the centre position to almost the upper end in the space of about 5 seconds, I turned the heater on full and it dropped again to the central position in about 15 seconds. Not sure if the engine fan came on that time as I couldn't hear over the heater. However I heard the fan come on this morning while sitting in traffic, the temp gauge never moved from middle, then the fan turned off after a few seconds. When parked about 15 minutes and 2 miles later the fan came on as soon as I switched the ignition off, this never happens. On and off off the ignition a few times and the temp gauge rose to maybe 3/4s but dropped again fairly quickly. There seems to be evaporated coolant on the heat shield under the expansion tank but I can't see the level as its dark at the moment.

Any suggestions? Do I have a coolant leak of should there be coolant spilled on the heat shield underneath. Do I have a sticking thermostat or is it kicking in as expected . Do I just top up coolant levels and hope for the best or take the car to the garage?

All advice very much appreciated!!!

[..Blackadder..]

Could be a split header tank is a known fault defo check your coolant level then get it to a garage to get it looked at.

[quenching]

Thanks for that, took it to local independent, he couldn't find any leaks, so he bled the system, lots of air in it, topped it up and left it run for a few hours, no drop in level and no overheating. None when driving either, so I'll keep an eye on it for a few days and see what happens.