Truth is that BMW had numerous customer "concerns" because the temp
> gauge would reflect the load on the car and ambient conditions. IOW it
> behaved as a temp gauge should. So they put in the buffered gauge as a
> peace of mind solution for the great mass of the ignorant. Of course
> you'll now get little warning of a cooling problem with a gauge
> climbing inexorably toward the doom level. Instead everything appears
> A OK and then a rapid rise to the peg. You've got about 10 seconds to
> kill the engine and park it.
Sudden overheating problems are usually caused by things like a fan belt breaking or loss of coolant. And you have warning lights for both of these. My 'other' car has a normal temperature gauge which when hot reads between
85 and 100C. So that's its normal range. Can't see a problem if a computer monitors this and keeps the gauge central while within this range.