OK, here’s your beta test for the new site: I have a 95 M-3 that I’ve had since new. Over the years, the temp guage sometimes stays at 0, or goes from a mid range to 0. Even under warranty, BMW couldn’t figure it out. The car has run almost issue free since new, and still faily low mileage.
Sounds like a calibration problem some one was too lazy or cheap at the dealer’s to do anything about till it became your problem and not theirs.
Now that it will cost you, they may be more than willing to rectify…by the hour of course.