rxpclb

Dear Audiworld,

I have a 2008 3.2 A6 quattro with a little over 80,000 miles on the odometer. I have owned the vehicle since July 2018 (56,000 miles). The AC was working fine when I bought the car, but stopped working back in March after I had it serviced at my local Audi Dealership. I didn't worry about fixing it at the time because the weather wasn't hot. I had my local Indie mechanic look at it yesterday and he thought it only needed freon added to fix the problem. He tried to add the freon, but the gauge he put on the line stayed at (0) after he tried to add some to the system. He said the freon was leaking out through the compressor, which he said was located behind the front bumper. He said I would need to replace the compressor to fix the problem.

My question is do these compressors leak and wear out over 10-12 years or do they have a release valve somewhere that could have been loosened somehow allowing the coolant to leak out? The Dealership wants $150 just to look at it and diagnosis the problem. I'm not confident my Indie mechanic can fix the problem. What do you think is going on?

jonzie77

I had a similar issue on my 2008, 3.2 Quattro, turned out to be the ever-popular temp/pressure switch located on the left side of the condenser ahead of the radiator. I would suggest depressing one of the schrader valves momentarily but fully if you get a rush of refrigerant then chances are you have enough (protect your eyes). After you put in a new switch you will have to clear a code in the Heating/Air Conditioning module or else the compressor will not come on. If your indie hasn't worked on this type of compressor he may be fooled since it is always "running" even when it is not actually producing cold air, I think the only thing that stops it from running is the econ switch next to the auto switch. My local Midas shop was able to get mine filled once I alerted them to the code that keeps the compressor from running. It would not stay running because of the bad switch which can be replaced without loosing but a whiff of freon because it is isolated by a schrader valve. I bought mine in 2017 with about 145,000 on it and since I bought it in March I didn't notice the malfunctioning air conditioning. Once I got it working it hasn't given me any trouble since. Good luck.

jk1391

It's on the left? do you mean driver?(us) The videos I've seen its on the right side of the condenser. pretty sure this is my issue also same model/year as yours. Do you have the part #? Going to tackle this one soon

jonzie77

Most car-related items are referenced from the drivers perspective so it would be on the left, right if you are facing the car (US). A quick search shows the part number to be 4H0959126B . You can find them from $15 all the way up to over $100. I seem to remember paying around $30 and it is still gong strong. Keep us updated on your progress.

jk1391

Thanks, I went on the audi site and there seemed to be quite a few sensors yet I couldn't find the exact one. Even the audi site doesn't show it up front, but once you click "what this fits" it shows the year and model. I will likely do this in a week or to - since it seems relatively easy. Then update if it works
https://parts.audiusa.com/p/Audi__/6...H0959126B.html

stifster

I had 2 holes in my evaporator. But it the indie AC mechanic insisted it was the compressor and replaced it ($2500). $2000 later I now have a new evaporator (which is a MAJOR pain to replace (dash and centre console has to be completely pulled out).
If it's not your switch - I'd give an A/C sealant a go (there are a few on the market) and either sell it, or hope like hell it fixes the hole.

I have a spare compressor if you want it...