BMW Repair: Coolant gauge needle in RED zone, 1998 bmw 740il, blown head gasket

Question
Dear John,
I have a 1998 BMW 740iL and recently the needle of the coolant gauage in the instrument cluster always moved to the red field after just 5 min of driving. The coolant level was fine and the engine felt cold. After I continued to drive for extended period of time, the engine still did not feel hot at all, eventhough the needle still pointed to the red area. What could be the problem? Any feedback is greatly appreciated!

Answer
several possibilities, ranging from bad sensor to blown head gasket to bad dash unit....or the worst case....a combination of them.

From the sounds of it, I'd try replacing the temperature sensor first.  If the gauge went immediately to hot, then I'd suspect the dash unit.

Get this taken care of immediately.  the 4.4L engine is a good one, but these HATE to be overheated.