Engine Cooling problem
2004 Pontiac Grand Prix 6 cyl Four Wheel Drive Automatic 150000 miles
my issue with my grand prix is the temp is rising into the red, especially when my a/c is on and im driving on the street. I thought it was my thermastat I changed that two days ago and today it went into the red and when I cut the a/c off and the heat on it goes down. Please help I dont understand and I dont wanna damage anything by driving. By the way it doesnt do it everyday just on hotter days.