Q: What isn't working in my car? It's overheating only when I'm stopped in traffic or in a drive-thru.

It sounds like you may have a cooling fan not working. The cooling fan draws air across the radiator to lower the temperature of the coolant. This occurs at a specific temperature and a fan switch, usually on the radiator, turns the fan(s) on when the coolant temperature reaches that threshold. When the car is moving, the fans are not needed as air flows across the radiator due to the movement. When you’re moving slowly or at a stop, the vehicle needs the fans to be operational to prevent overheating. If the fans are not coming on, the temperature of the coolant continues to rise until the vehicle ultimately overheats.

The root cause of the problem could be as simple as a fuse/relay, or it could be a fan switch, fan motor(s), or a wire harness issue. A quick visual inspection of the fuse can determine if that is the cause. Also, a check for battery voltage at the fan motors with the engine running and warmed up can determine if you have a fan motor inoperative. If there is battery voltage and good ground for the fan motors when the engine is hot, then the electrical system is operating properly and the fan motor is the culprit. I strongly recommend an experienced technician aid in diagnosing to prevent the replacement of unneeded parts. YourMechanic has several available technicians that can assist you with finding the cause of the car overheating issue, and provide an estimate and direction of repair.