In Reply to: Overheating problem, everyones help needed posted by brian on June 09, 2001 at 07:11:52:
Remove your radiator and backflush it. Earlier M3's had the sensor in the rad - but it's too low down and if the rad gets too much silt/crap in the bottom, the rad develops a cool spot and the switch won't kick in.
Later cars had the switch put in the thermostat housing (the 3 way heart type valve). This sorted it out.
Hope it helps