gordon_gjs

Hello All,
AC went out on my 2010 Audi Q5 3.2L on the way from work today. The past few days it seems to have a hard time blowing cool air at stop lights or blowing cool air within the first few minutes of start up.

Here are some things I checked for...

1. Fuse on passenger side is good
2. AC Gauge reads pressure high
3. Compressor doesn't appear to be running but looks like it is spinning still when AC is off
4. System appears to still have freon in it

The pictures are from the OBDeleven. I took screens shots with the AC running and the AC turned off. But I am unsure what to make out of the AC compressor Values, they do seem low to me when on.
Any ideas?

AC OFF:




AC ON:

gordon_gjs

Update
Can anyone confirm where the AC Compressor is on the 3.2L V6? I am guessing it is on the bottom driver side corner of the motor?

I attached some pictures of what appears to be damage to the front of one of the pulleys, you can see broken plastic pieces on the outside edge of pulley.
Check out the pictures below (Sorry for the bad pictures, I will try to take some better ones tomorrow if they help).







***Let me elaborate on the bolt not moving, it doesn't spin while the pulley spins, even with the AC off or on.***

MP4.2+6.0

No experience w/ 3.2 specifically. But going by pics I would say the pulley assembly is blown. Compressor is likely behind it. Had this on my 2006 W12. The pulley--at least on mine--has a sacrificial rubber based one time fail clutch. Audi A/C compressors don't have an electric type on/off clutch and so spin internally full time. Modern VW's have a similar set up with this pulley set up from searches I did at the time. The sacrificial set up is so if something goes wrong it does not lock up pulley itself and then burn and destroy the serpentine belt with motor turning when on the road.

In my case I was lucky. The pulley had simply deteriorated. Audi sells it as a piece part. I installed new one and all was good. I still can't explain except simple age and wear and tear why it failed on mine. Maybe 4 years ago now on mine and all still good. The larger $$$ question is whether on yours the compressor also failed. If center shaft spins like mine did it is likely fine. But if locked up or you hear obvious grinding or some such when trying to turn, not good. With destroyed pulley still on there, you may have some trouble figuring out if compressor can turn. Serpentine belt has t come off of course. Took me a while to get the mangled pulley remnants fully off in order to replace. If by chance you used the $20 "seemed like a good idea at the time" refrigerant top up stuff BTW, that can lead to an unfortunate overfilled result where it blows the A/C cmpressor in a scenario like this.

You should pull belly pan from underneath and confirm that is A/C compressor. Look for the refrigerant hoses going to and from it. Fill point will be somewhere accessible up top in the low side pressure hose. Trace it from there or the high pressure side ultimately to the compressor.

gordon_gjs

Thanks for info! I am going to get a closer look at it tonight when I get off work. Should the AC compressor spin freely by hand with the system pressurized? or maybe with a tool?

MP4.2+6.0

Compressor won't free spin or keep going when you turn it, but shaft should be turnable with modest wrench (or pliers if need be if the pulley is wiped out internally ) and without any mechanical noises. Feel is like a light very small compression motor IIRC, which is sort of what it is. It works on a variable displacement basis, so on Audis is is always engaged to an extent. On a classic old school American design, it would have an electrical clutch that you hear click off and on when running. With motor off on a clutch type, the clutch then free to spin, but not on these.

MurrayA4

Always the first place to look on an Audi for this type of issue is the AC pressure sensor.Easy to access (on the condenser) and cheap to replace.If you can scan your vehicle with VCDS it'll show the origins of your failure.But definitely have a close look at that pulley.As MP4.2+6.0 suggested.

gordon_gjs

*Update* *Also thanks to all who have posted*
So I got a better look under the car. It looks like the AC Compressor is seized up
I took out the mangled clutch and tried to spin the compressor both clockwise and counter clockwise with a ratchet and I can only get it to spin half way in both directions, doesn't feel smooth at all during the half of spin.

Now time to to see how hard it is to replace the AC Compressor. Can anyone post up instructions? I would greatly appreciate that.
Does anyone know what needs to be remove in order to replace the compressor? I plan on doing this on ramps, is it possible?

Kelli Miguez

I'm hoping someone can help you with how to change out the compressor because my 2009 Q5's compressor looks just like yours and I am also searching for answers. From what I understand, we will have to empty the high pressure lines before taking the compressor out, which I believe can only be done with a special machine. I'm hoping it doable though because I was quoted $3000 to change the compressor out. Yikes.

gordon_gjs

Hey Kelli Miguez, I ended up replacing the compressor over the weekend. It took me 2 whole days with the help of my brother. I probably could have finished it quicker if I knew the issues/extra parts I would of needed.
As for the special machine to empty the high pressure line that would be the recovery tank so you do not vent out the R-134 into the atmosphere. You should be able to take it by most shop and have them evacuate the system for you.
If you skip that option and do not have the recovery tank then your only option is venting out into the atmosphere (which could carry fines depending on what state you live in, just keep it your secret).

Here is a list of items I wish I would have known about before starting this project:

1. This car requires a large bore schrader valves removal tool (Autozone/O'Reilly did not have this tool). I had to travel 30min one way to Napa Auto to find this tool. I would have ordered on Amazon in advance if I would have known this. It would have saved around 2 hours of time.
2. I had to remove the oil cooler to remove the AC Compressor. This requires a new oil cooler gasket, oil drain plug and oil drain plug crush ring because you have to drain the engine oil. Luckily it was Saturday and the Audi dealership was still open. If I would have known this I could have pre-ordered the gasket and saved me at least 1+ hour of time.
3. The o-ring kit I order did not work out for me so I had to re-use all the old o-rings (they were to thin compared to old o-rings).
4. The AC expansion valve I ordered was the incorrect one, it looked identical but the tube size bores were to small and it wouldn't fit on so I just reused the old one. If I knew it wouldn't have fitted I could have saved around 3-4+ hours time by not messing with it. My advice to you if not to mess with it unless you know it is bad. It is just a pain to get to. The inside of my AC system looked clean so I am not sure if a new expansion valve was needed.

Cost was around $500 and that included an oil change. I was able to borrow the a/c vacuum pump and a/c manifold gauges from a friend. This saved me $150+.
Harbor Freight Price for A/C Pump and Gauges:
A/C Manifold Gauge = $60 (Before 20% Off Coupon)
A/C Vacuum Pump = $100 (Before 20% Off Coupon)

Here are a list of parts I purchasedAll Prices from RockAuto)

• UAC CO11271C {#4F0260805AF} - A/C Air Compressor (RockAuto) = $270
• OSC 3868 {#8K0260403E, 8K0260403M} - A/C Condenser w/ Receiver Drier (RockAuto) = $60
• Valve Stem Kit = Roughly $5
• O-ring kit = Roughly $10
• PAG 46 Oil = Roughly $7
• 2 Cans R-134A (One with UV Dye) = Roughly $5 Each
• Oil Cooler Gasket = Roughly $7
• Engine Oil & Filter
• New Serpentine Belt (Gates) = $22 (If needed, mine was due to be changed)
• New O-Ring for Power Steering Pump (Line needs to come off from power steering pump)
• Power Steering Pump Oil (Rated for Audi)

As far as a manual goes I purchased a 1 year subscription manual from ALLDATA. It was about $15 for the year after I found a promo code on Google. Wish I would have purchased the manual way sooner, there is a lot of usual information in it. I am looking to tackle and replace the sunroof retractable shade soon as mine ripped off the track many years ago, the manual will come in handy for this.


Here are some pictures from the install. Hopefully the pictures are not to large. Also excuse the oil mess on the engine parts. I had the infamous valve cover oil leak which I had already fixed last year just never detailed the engine/components.

Kelli Miguez

Wow, that is so helpful gordon_gjs! Thank you so much for taking the time to post pictures and all.