Had this car since new and never had a problem until a few days ago (66K on the clock). Wife sat in a traffic jam for 1.5 hours with the AC on and the needle started to climb. She caught it before it topped out and pulled over. Had it towed home and I replaced the thermostat -- even though there was no indication that it was bad.
The water pump is good - no leaks or bearing whine, and the coolant/radiator appear to be good. (been flushed and filled several times since new). The fans work fine, shift from low to high as the car warms up, and it will not overheat in normal driving. The sensor passes resistance tests as set forth in the manual. Hoses are new and coolant circulates as one would expect. Can't find a "hard" cause/problem.
My wife is now afraid of it and won't drive it until it is "fixed." Anyone have any thoughts or experienced similiar problems?