Hi-
I have a 2000 S70. The A/C blows cool until the car idles, then it blows hot air that smells musty. Do I just need freon or could it be something else? I haven't specifically asked for freon to be checked with tune-ups. Is that something I should specifically ask for or is it something automatically part of tune-up? NOTE: I do not take the car to dealership for repair as it is out of warranty.

Thanks!

I've encountered the same problem with my 2000 v70xc. At an idle at a drive thru or in heavy traffic, the air will go away. If I turn it off for a few seconds and turn it on again it starts working again. The mechanic I took I use told me it might be the magnetic clutch on the compressor that volvo uses. Over time the two magnetic plates (that are attracted to each other to engage the compressor) get slightly further apart and the high heat in the summer may be increasing the gap so that the two plates can't grab each other and start turning the compressor as it tries to cycle on and off. It was only a guess by him because he hadn't looked at it and there is no fix other than replacement. I live in a rural area so my car is not at idle for long periods of time so this is not a problem for me. It was on my vacation to Atlanta in heavy traffic. I would have it fixed if I lived in a city.
The mechanic only works on Volvos and BMWs so he is pretty reliable but still it was just a theory suggested by him.

I've been checking on the magnetic problem with the AC clutch. It seems it can be adjusted with shims, but it still involves taking the compressor off.