I know of problems with some instrument clusters where the speedo needle would stick to the resting peg due to the paint on it getting sticky. Maybe you are experiencing a similar problem with the coolant temp gauge if it does have a painted resting peg.

__________________
Ali Al-Chalabi

2001 CLK55
1999 Dodge Ram 2500 Cummins Diesel
2002 Harley-Davidson Fatboy
Merlin Extralight w/ Campy Record