So I picked up my 300D this weekend and drove it home. I noticed that the temp gauge was riding a hair below 80*C. Not really concerned as the needle was still touching the 80*C line. I've driven it daily since and noticed the same.

This morning, we had one of our first mornings below 40*F. Car warmed up fine, but on the 30 min drive into work, I stopped getting heat. I cranked the ccu up to max and selected "auto". I got cold air that continued to get colder... that's when I noticed the temp Gauge was down below what I call the 60*C line (the mark between 80 and 40). I put the ccu on economy and the fan on low. Within 5 minutes I could feel heat coming back and the temp gauge went a mm or two above the 60*C mark, but no further.

I'm thinking that the thermostat is stuck open and needs to be replaced.

Your opinions?