[.quantum.]

My Grand Prix recently began heating up very quickly if I'm stopped in traffic for several minutes or going through a drive thru, almost going into the red. Once I get moving again though, and the car is getting airflow, the temperatures quickly return to normal. When I got home today, I popped the hood and saw that the radiator fans were only running if the AC was on, but at that point the temp was normal....

I'm hoping it might be as simple as a bad thermostat.

Any ideas of what the issue might be or is there more information I need to give out?

Also on a somewhat related note, I noticed my coolant resivoir was low, so I added some dex-cool (about half the bottle) but forgot to mix with water, How bad is that? Should I drain and refill the cooling system?

Thanks.