I have a 2008 impala and the heater has quit working 3 times now. the first time the car only had 10000 miles on it and the dealer flushed the cooling system and adjusted the heater ( they told me there was a service bulletin on it). It worked good for another year and quit again they said the heater core was plugged and flushed the cooling system again but now they say they never had this problem before and don't know about any service bulletin. worked good for another year and the same thing good thing it was under warranty but now the warranty is up

Heater will not warm during the cold months had to take it to the dealership and get it checked out. They had to replace some of the pipes behing the heating unit with new ones. Then it corrected the problem for at least a month or two. Then it started again really being annoyed with this because, the dealership should be up to speed on this stuff. The dam car was purchased brand new back in Jan 10, 2008 at the dealership. Then the service guy ased me if your antufreeze was low I stated not as I know of, then he went on to say if you antifreeze is low then your heater will not warm. Something new to me and he added some coolant and it has so far corrected the problem. Bullshit as chevys That all I got to say.