I know my car has had cooling problems before and im going to change the thermostat after it cools off. When i open the hood after a nice long ride i smell a faint smell of hot coolant. Also, while driving the temp hand going over to NORMAL "A" and it goes down once i turn on the heat to full blast. Last time this happen was driving along and i didnt catch the temp past the A and the car almost overheated while driving (the temp hand was past the red line.. it was smoking so i guess it did overheat) . The coolant in the overflow tank was bubbling and was near empty. I think my thermostat is wearing out so im going to change that today and hopefully it stays at the NORMAL while driving w/o the heat/ac on. Does this sound like a bad thermostat?