[Chambers]

Also try burping the car, I changed the radiator fluid a few weeks ago and now sometimes when the car idols for long enough it will blow cold air, then when I rev it up a little and the heat comes back because the warm water runs through the heater core.

To burp the car, park the car uphill with the engine on the high side, keep it running, open the rat cap, I wouldn't try to do this while the car is warm, the pressure will spray hot rat fluid all over. Keep filling the rat with fluid until it fills, it can take a long time for the air to get out, Ive burped my car two times now and a little air is still trapped. If you don't have a hill use a floor jack, or ramps. From what I understand the higher the front of the car the easier the air will escape. Hope this helps.