OK, when I bought my 99 A4 2.8 30V back in November, I did so knowing the AC was not blowing cold. I did try a recharge using the R134a kit from AutoZone, and the system would only take a little over half the can, and the pressure would hover right around 25psi (the low limit of what is considered OK). When I turned the compressor off, the pressure went way up (above 60psi). I could see the compressor itself spinning, so I know that at least the clutch is engaging to drive the compressor, and the fact that the pressure drops when I turn the compressor on tells me that the compressor is OK. That leaves me with only one idea really - the expansion valve. I know that on other cars, this is often located right where the AC lines come through the firewall into the engine bay. Is this the case with the A4 as well, or did Audi hide it somewhere? Also, is there anyone here who has dealt with this type of AC failure? How much did it cost to have it fixed? I'm thinking that they'll have to replace the expansion valve and various seals and such, plus evacuate and recharge the system - should I practice bending over now, or is it a reasonable ($200-300) service?

Thanks for any insight you can offer - it's getting f'ing hot and muggy around here, and I have two little kids with me in the car on a regular basis. I don't need to tell you guys how hot a black leather interior can get. Any takers for this one?

 

The pipe that you added R134a to, has the small valve. It is located closer to the battery
than the high pressure line. It is thicker, and should be cold when the A/C is on.
You should only connect the can when the A/C is on. Try to heat the can with
your hands to empty it.