I have an '08 Impala LS and am having an issue with the heating system. Even after the car is warmed up, I still get cold air at idle. As soon as I pass 1000 rpm it blows heat. This is a pain mostly because I can not let the car run on cold mornings and come out to warmth and defrosted windows. Once in the car I can keep my foot on the gas when stopped (I am getting good at left foot braking), but that wastes fuel. My boss has the same problem in his Impala as well. It is a company car, so I can get it fixed at no charge, but would rather do it myself if it is simple (fuse etc). I hate leaving my car at the repair facililty for any length of time as it is a hassle. Just wondering if anyone knows the fix. Thanks.

 

Sound like it has a bad thermostat or is slightly low on coolant.

 

general motor has released a teachnical service bulletin addressing the issue you are complaining of. replacing head gaskets and bolts with upgraded gaskets and two diff corner bolts