Thank You Cliffmac and Tiny Panzer for your thoughts on my cooling fan and temperature issue with the '95 SL500. Two days ago was the first time in a year that the weather was cold outside (20 degree) and the roads and the roads were clear of snow and road salt that I could take the car out for a ride to get all of the fluids moving. The ride was about 20 minutes and about 10 miles and usually this is enough to get the car relatively hot. I was surprised by the temp reading not being "high" enough for this car because it would normally run at 80 to 90 celsius. My first thought was to check the viscous cooling fan clutch to see if was "spinning" or locked up and cooling the motor off too much. The fan spun around easily, so I am just attributing this reading of 40 to 50 celsius as an anomaly related to the cold and 50 mph speed I was driving. I plan on checking the thermostat in the spring and the temp sensor you mentioned. Thanks, Steve