My car's AC blows hot air when I am stopped at a long traffic light, just idling, or driving very slowly...?

Question

... such as when I'm circling around in a parking garage, but the AC works just fine when I am driving normally.  

A friend said he thinks it's the compressor.  Can anyone confirm that?  If so, how much do you think it would be to fix? My car is a 1999 Saturn SL2.  

Any recommendations?  If I decide not to fix it, is the AC likely to stop working entirely?

Thanks for your help!

Answer 1

My suggestion is to get it diagnosed somewhere you trust.  It should cost about $30 to find the problem, then you'll know.  

Off-hand, it could be the compressor, the drive belt or low/missing coolant.

Answer 2

Check the refrigerant level. It is probably low (you'll need a qualified tech to do this but it's not expensive, under $150 even with a recharge)