my MIL was on and off every other week since buying my compass in December of 09 I assumed temp sensor but was told it was a loose air intake letting air in that shouldn't be coming in, and if it happened again to come back to the dealer, and when it did... I did... only to be told in a hush voice by the girl at the service counter to take it somewhere else I had a warranty and I would be better off.
Lovely to hear from a place I just spent 15 grand for a used car.
Annoyed I put it off as long as possible cause every time I thought about it I would get pee'd off. It wasn't until the warm weather hit that I noticed my coolant was low, the reservoir always looked full in the winter because the thermostat was closed. 5 bucks for a quart and the check engine light hasn't come on since; I continue to watch it though, I don't want it to be leaking or burning, that would be a much bigger problem; so far everything looks good!