[CREWZIN]

I'm almost positive the water pump is mechanical so when it fails it fails and either leaks a lot from the front or doesn't let the coolant run around the engine to cool things off so you wouldn't have the times you say it doesn't overheat without the A/C on. It would overheat all the time.

Good luck at the dealer. Make sure yo have them run the engine with the A/C ON to see it overheat. Please come back and let us know if/when they find the problem.