My 98 V70 AC works fine and puts out cold air when you first start up. After a while it cuts out and actually starts pumping HOT air into the cabin. (I'm thinking this happens at about the time the engine comes up to temp.) Sometimes you can shut it off for a while and get it to work again for a few minutes but not reliably. The dealership said we needed a new compressor @ $1800. Obviously the compressor works because it delivers cold air, but they said there's another part that is integral with it that failed. Does anyone have any idea what that is and if this is for real? Could it have anything to do with a thermostat? Thanks for everyones help.