BMW North beat me to what I was going to say.
However in the event you find your car overheating again, do the obvious and pull off to the side of the road. Instead of turning the car off all the way, keep the key in position 2 and turn the heater on high. This will help the engine cool and may even save a few people from getting warped heads.
Originally Posted by dmax
You did pray to your BMW shrine first, asking the Great Roundel for guidance on parts' choices first, right?