My 2000 Grand Prix is overheating, mechanic doesnt know whats wrong with it.
My car was saying low coolant when I turned on my car but the sign would go away after a bit of driving. A couple days later I put half a gallon of coolant in. The next day my car began to overheat for the first time so I pulled over and put the other half of the gallon in and drove home with no problems. Yesterday is the first time I drove since the last overheating incident and the guage began to go up after a couple minutes of driving. It was close to the red zone but I managed to make it to my destination. I went to my mechanic to have him see if there was a leak or something that could be causing this problem. After an hour of waiting he told me he checked everything that could possibly be causing the overheating and he couldn't find a thing wrong, other than my battery being close to dead. SO I am completely stumped.... Any advice?