My 560 SEL runs fine at normal speeds with the enging temperature gauge staying in the middle of the band. When I am at idle for a few minutes the temperature starts to climb pretty fast. The outside temperature sensor also starts to climb. As soon as the car gets going again the temperature come down to normal.
I "Think" that I can smell coolant under the hood however I have not noticed any significant change in the expansion tank level. The fan seems to be running fine as well. Any chance that I have a defective cap on the expansion tank? Where else should I look?