Hello, it was a very cold morning today. Well I let my car run for about 10 minutes before leaving for work, on my drive to work I turned the blower up to high on my defrost. I noticed the temperature gauge dropped a few degrees-like maybe 2 or 3 marks. So I turned the blower back down and it went back to normal half way mark. I'm hoping it's just because it's cold and not a major issue. Also the exhaust smelled like rotten eggs; don't know if that has anything to do with it or not.
My car has 84000 miles.
My car has an automatic transmission.
When the heater is being used the heater blower blows air across the heater core to blow heat on the window for you. The heat is supplied by the engine coolant circulating through the heater core. The use will remove heat from the engine coolant and you may notice the temperature gauge drop some when heater is in use. This is normal operation.