I have a 03 cadillac deville dhs. The car has 79k miles. I just recently changed the radiator and the thermostat. When i ride for a couple miles with the AC on the car will start to run hot. When I cut the AC off the car will begin to go back to the middle of the temperature gage. When the car is in park and. Idiling it will not run hot. I checked the fans and they both are working. If I am just riding with the AC off the car will not run hot. Any other suggestions on what is causing this?