Q: Car overheats and air conditioner not working

While having a broken A/C is a big inconvenience, having your Pontiac overheat is a much bigger concern that we will need to addressed first. When your Grand Am overheats, the temperature rise inside causes damage to the engine and its components. You mentioned you had a mechanic look over the car previously but it is unclear by the description if that was a proper diagnosis or an estimate.

A head gasket replacement is a major job for your Grand Am and the diagnosis should be sure before moving forward with the job. There are a couple of tests a seasoned mechanic can do to give you a solid diagnosis. The first test I would perform is a cooling system pressure test. This test allows me to pressurize the system and check for signs of any coolant leaks.

If the system is loosing pressure and I do not see a leak externally, the next test I would perform is called a block test. This test takes place with the engine running, using a special tool that looks like a clear tube that holds a special fluid that turns from blue to yellow if exhaust gases are detected in the coolant. If exhaust gases are detected in the cooling system then it is indeed likely the Grand Am has a failed head gasket. I would have a professional mechanic inspect your car’s overheating and AC issue as soon as possible.

After the concern with the head gasket is addressed, your professional mechanic will also be able to look into why your Pontiac’s A/C is not working.