On my '05 A6 the A/C works fine until it has been running for a while then it just blows cool, on our trip to Boston this past weekend we actually had sweat running down our checks, I tried a lot of different set ups and finally found that putting the recerc on helped and the car started to cool off. System charge is where it should be, we also noticed a week ago that when we first started the car that we got quite a blast of really hot moist air from the vents anyone else have this problem or is it known for these cars.

 

Audi has issued several TSBs regarding the AC. Take a look in the HVAC section of my TSB library. Here is a link to the library.

http://uberlame.com/a6_tsb/