We bought the 2005 Impala 2 years ago and never had real heat. I had the system checked out in the engine compartment to make sure that hot water was running through the system and also had the radiator flushed, but still just get warm air. Is this typical with this year and model?

 

check your thermostat. It is probably defective. I had the same problem with my 03 impala. One day I let it idling for a long period and my gauge went higher. After that the heating was perfect for a while but the gauge went back to the lower readings a short time after. The thermostat was the culprit. A quite a big job to replace on the 3.4 liters.engine.