Well since I got my car out again for summer, the heater doesnt seem to work. It still blows but only cold air. I have a manual fan switch and hardly ever turn them on in this tempature. Well i just hope its not the heater core. There is no air in the coolant lines either. :nonod: I about froze tonite

 

Well it could be the valve that directs air to the heater core OR bypasses it.
All air goes through the evaporator core (wether the A/C is ON or OFF) and a valve then guides it 100% through the heater core aswell or bypasses it 100% or anything in between depending of the valve position.
This valve is the ONLY valve that is cable controlled and not with vacuum unlike the other valves (defroster, floor, dash, vents).
It could be that the cable is disconnected or something.

Might be worth checking that control panel (with all the vacuum hoses on the backside) and to see if that cable moves if you turn the cold/warm selector dial.
If that valve is not operating properly inside the HVAC unit or the valve is broken or something then you would have to remove that entire unit and your in for a treat, probably requires taking that entire dash apart.
I have never read though that somebody had problems with that valve itself (mechanical).

 

Might want to try flushing it. There are some instructions here for ya...

http://web.camaross.com/forums/showt...hreadid=191218