My 2002 Impala 3.8 has been running great. However, this summer the thermostat gauge stopped reading temperature right. To the point it wouldn't move even after it had been running for hours. It would just stay below 140 which is the lowest temp marker.
However, today, with a high of 21 here in Texas, it started to just creep up to the red. The deal is, when it gets to the red, it's not really that hot. I can turn my heater on full blast and have the air pass over the engine and the air is still coming out cold.
My car is telling me that my coolant level is low too, however I just checked it and it's perfectly fine.
What in the world could be going on?