96 850 GLT Air cond. intermittent

My 95 850 had similar symptoms. I had AC recharged and it lasted about one year. Then recharged again and it lasted about a week. Problem was leaky evaporator .... depending on where you have it replaced (not a job for the faint hearted shade tree mechanic !!!!) it will run $1000 to $1600 for a new Volvo evap, dryer bottle, and several O rings. Suggest you have the 6 instrument panel illumination light bulbs replaced while the dash is apart and also the recirculation plastic arm (if a white part, replace. if a black part, it has already been replaced).

Good luck.

" In slow town driving or while parked the AC will suddenly blow slightly cool or warm air."

OK, mine does that as well it has been doing it for 3 years. It ONLY does it when I am using the AUT setting that lets the car manage the temp inside the cabin. I have never added freon. To wit: I was driving to work this AM and it was 75 degrees outside. I had the temp set to 72 and had it on AUT and it's was like it wasn't even blowing. So I manually adjusted the fan speed up high and here came the cool air. Moral of the story, don't use it on AUT. I don't in particular at highway speeds, as the cycling bugs me. It will turn on and off once every minute or so. If you turn the fan up and the temp down it does not cycle. Try it, and see.

Heh, the cycling comes because you need to add som R134a to the system.. (10% of it just disappears every year) Got mine refilled friday, and damn what a difference.. They also put in something called ProSeal that should take care of any leaks up to 2,4mm in size.

Same thing, '96 850 GLT, new evaporator after 54,000 miles and at 104000 miles, 4 years later, need another one, legendary Volvo part failure on this model, can fill with freon every year but time to bail on this car I'm afraid. dealer won't help with this one.