Q: Car overheating and not starting

You certainly don’t see many Pontiac Torrents around. The 3.4L is a common engine, however, and I know it well. Since it doesn’t use a timing belt, I assume you must mean you replaced the serpentine belt. The only way I can see this being related to your overheating concern is if the belt was not properly installed. This is because the water pump is driven off the serpentine belt. If this is the case and the engine overheated as a result, the head gasket/cylinder head may have been damaged. Both can fail due to engine overheating. If the head gasket is blown, hydrocarbons (unburnt fuel) will be able to enter the cooling system. A block test is used to test for these exhaust gases and diagnose a failed head gasket. A qualified technician, such as one from YourMechanic, can diagnose and repair your car’s overheating issue promptly.