My 06 Cobalt LT was blowing smoke from the A/C. I replaced the thermostat, changed the oil, the filter, and added coolant. After I fixed everything, my car ran perfect but it was still reading 270 degrees and the car wasn't even hot, no smoke blowing from the A/C. I assumed it was the sensor but the car was fine. A week later, the car acts up again, blowing smoke and overheating. I pop the hood and touch it, the car isn't even hot, yet it's reading 280 degrees and the coolant is gone. I realized that the car is leaking coolant from the firewall. I don't know how to fix it! Can someone help?
