3.0 A/C Compressor DIY + Flush/Fill

[cschuster]

Completed a compressor swap this weekend, here is a quick DIY so you know what's involved. Mine leaked out all the refrigerant upon rapid disassembly, so the recovery portion did not apply. If your system still has refrigerant in it, you will have to get it evacuated first. Don't get bent over at the shop, you can do this with a few rented tools. It cost about $175 bucks total. You will need:

Parts:
Coolant
Oil + filter
Oil cooler seal - parts websites are not correct. Use this one.


Compressor - there are 3 splits according to ECS. up to '02, '03-'04, '04+. Got mine used from Tom's foreign for 80 bucks w/6 month warranty
A/C Drier
A/C Orifice Tube
A/C Flush
134a - Two 13oz cans. No stop leak or any other crap. Compatible with PAG oil.
PAG 46 compressor oil - if yours doesn't have any already in it.
O-ring kit

Tools:
A/C Flush Kit - rent from Autozone
Vacuum pump and manifold kit - rent from Autozone
Air compressor
134a can tap.
Digital gram scale
Gloves and safety glasses. Good PPE

R&R + Flush/Vacuum:
Service position.
Drain coolant and oil. Remove filter.
Remove connections from drier, orifice tube, evaporator, condenser.





Remove orifice tube and discard. Unbolt drier and discard. Swap in new drier to housing, keep the plugs in for now. Swap over the roll pins from the old drier.







Unbolt A/C line from oil pan (passenger side).
Remove right hose from oil cooler. Or remove both, I just did the one because it was easier.
Remove 27mm nut



Slide off cooler. Either remove it completely or wedge up out of the way.



Remove 3 bolts from compressor. 2 are easy to see, 3rd is in the back. Now the compressor should be free and easy to pull out of car with lines attached. I removed the lines after due to torx access.



Flush all lines, compressor, and condenser with the kit + air compressor. Be thorough and blow out with air afterwards.
Install new orifice tube. Remember how far in it was when you pulled the old one out? It takes some force to get it all the way back in place.
Install new o-rings on all connections.
Add oil to new compressor, turn the pulley so it drinks it up. See manufacturer specs for quantity.
Bolt lines to compressor and install.
Bolt orifice tube, condenser and evaporator lines.
Now install the drier and remove the plugs, then install the connections. The drier is a desiccant and will soak up moisture in the air. Do not leave it exposed longer than you have to.

Hook up manifold to high/low lines and attach vacuum pump.



Turn on pump and open high/low/middle valves. You should see low gauge drop to -27ish psi of vacuum. If it does not, you have to find the leak.



Run pump for 15min, then close both hi/low side manifold and shut off pump. If gauges drop after 15min, you have to find the leak. If not, vacuum for another 15min.



Leave manifold attached.

Install new oil cooler gasket. Slide cooler on, then attach the coolant line(s). Put the nut back on and attach filter.
Fill oil and coolant. Install belt.
You can either charge the system now, or put the bumper back on and charge at the end.

Fill:
Screw tap onto can. Weigh both together and write it down for future math. Total weight needed can be found under the hood.



Hook up can to middle yellow line. Screw tap down to puncture can, then unscrew to open it up. Purge air from line by unscrewing yellow fitting at the manifold until a little 134a comes out. Subtract 50g from original weight.
Place can in pot of warm water.
Start car. Set to LOW and put max fan on.
Open LOW side all the way. The gauge should start to go up. NEVER OPEN THE HIGH SIDE WHILE FILLING!



ECON light will be on, and the A/C pressure switch will be off, so you have to fill half of the first can and then turn off car.
Start car, ECON light should be off now. Resume filling until can feels empty.
When empty, close LOW side and middle valve. Close tap on 134a can. Remove can from line, then weigh it. This will tell you how much refrigerant went into the system and how much you have left to fill.
Swap tap onto 2nd can. Repeat hook up and purge process.
Start car, open middle and LOW side valve.
After 5min or so, the gauges should look like this now. Your pressure will vary based on ambient temp. Icy cold goodness should be flowing out of the vents.



When empty, close manifold valves, shut off car and disconnect can like before. Weigh and confirm the amount added is in spec. 2 cans gave me 510g.
Remove quick connects from HI and LOW ports.
Enjoy the summer heat! Sorry for all the sideways pictures...photobucket wouldn't let me rotate.

Here is the autopsy on my compressor. The pulley bearing failed and the seal was damaged. I didn't really have to flush, but am glad I did anyways.

[hightime80]

You are one handy cat👍. It was thx to you that I figured out how to put my s4 cluster in. Sure wish you owned a 1.8t instead as I m sure my original ac compressor will bite the dust sooner than later.

[cschuster]

You are one handy cat👍. It was thx to you that I figured out how to put my s4 cluster in. Sure wish you owned a 1.8t instead as I m sure my original ac compressor will bite the dust sooner than later.

1.8t should be a similar process, as the compressors are in the same area. Flush and fill procedure is exactly the same.

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[pablolizarraga]

Bumping this great thread for fellow 3.0’s and just in time for summer. Glad I stumbled onto this because my previous google searches and links never came up w/ this thread.


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[DarkoNova]

Man, I should probably do this since the car is in service position and my AC doesn't work....

I just don't want to spend more money lol.

[pablolizarraga]

Do you know what’s wrong? Compressor? Leak? Clogged orifice tube?
I know my compressor is shot; pulley bearings. But I also know I have a leak as well. However, leak dye test was inconclusive as I didn’t see any leak sources. Although I pumped enough refrigerant to get the ECON light off, I’m not sure if the compressor was functional. So, I’m guessing all the leak dye is still in the compressor?


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[Turbo510]

I disabled my pulley with the noisy bearing before compressor damage could occur- at least I hope so, with a shorter serp belt from AutoZone. I also have the new bearing on hand, and just received my special Denso compressor drive plate removal tool today ($52). The front end has to be in full service position though, to have room for the impact driver.

[DarkoNova]

Do you know what’s wrong? Compressor? Leak? Clogged orifice tube?
I know my compressor is shot; pulley bearings. But I also know I have a leak as well. However, leak dye test was inconclusive as I didn’t see any leak sources. Although I pumped enough refrigerant to get the ECON light off, I’m not sure if the compressor was functional. So, I’m guessing all the leak dye is still in the compressor?


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I have no idea. I just know that turning the AC on does nothing. Air doesn't get colder, I don't remember if the rpms change at all. I never scanned it specifically for AC problems. Right now the car is apart for a clutch job and the battery has been disconnected, so the codes are probably long gone.

I had no idea you could rent HVAC tools from AutoZone. I might put the old coolant in just so I can let it run while checking manifold pressures, lol.

[pablolizarraga]

I also have the new bearing on hand, and just received my special Denso compressor drive plate removal tool today ($52).

Didn’t think that you could replace bearing on these compressors. What’s the part number on the bearing and from where did you source it? Ditto for the special tool.

I had no idea you could rent HVAC tools from AutoZone. I might put the old coolant in just so I can let it run while checking manifold pressures, lol.

You actually borrow them w/ a deposit that’s returned when you’re done w/ tools. You can get manifold gauges and vacuum pump.

Easiest diagnostic thing you can do would be to press the schraeder valve on low pressure line to see if you have any refrigerant. Since I don’t have refrigerant (I know I have a leak) I can inspect/replace the orifice tube.

Next would be VCDS scan. I had a “00819- High Pressure Sensor (G25) 07-10- Signal too low- Intermittent” code. Replaced that G25 switch but still no A/C. Other threads cited codes for problems w/ vent flaps that had to be re-set via VCDS.

With that info, then it’s up too you on how far down the rabbit hole you’re willing to go. At the very least, you’ll be much more informed if you have to get it serviced by a shop.



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[DarkoNova]

That's weird, they don't show anything but the flush tools in the a/c loan-a-tool section on their site.

I pressed on a Schrader valve, but I forgot which side it was on, and refrigerant came out. I also mistakenly cracked a bolt loose on the compressor and refrigerant came out as well.

[pablolizarraga]

It may not show online, but just ask them at the desk. At least, Cali stores since have them, since another store had them available to borrow.

Well, that’s a good sign. At least you don’t have a leak to hunt down. Let’s see what VCDS tells you. If there are A/C related codes, they’ll show up when you try A/C again.


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[Turbo510]

Didn’t think that you could replace bearing on these compressors. What’s the part number on the bearing and from where did you source it? Ditto for the special tool.

I bought both on Ebay; the bearing from "theaccompressorworld", $7 I think. I haven't installed it yet, but I'm pretty sure the size is correct: 52mm OD, 35mm ID, 22mm wide. I'll also find out if it really is just press old out, press new in. The bearing is marked "Global Air" and "CB-1106"

The clutch removal tool is item number 142684254799, and listed as a Mercedes AC clutch removal tool. However, the same or very similar Denso compressor is used on the 3.0, the seller wrote that he tried the tool on a pulley hub for a 3.0 A4 and it fit correctly.

[eddie916]

Great DIY! I was going to post a question as a separate thread, but maybe someone in here can enlighten me.
I did the install on my 1.8 and realized that the inlet manifold size was too small on the new compressor, but before I realized it, I took the yellow cap seal of the hose and ruined it a bit.
Also, all of the replacement seals seem thinner than the originals - which should I use?

Are these necessary? (I would imagine yes)
Are they replaceable? (I couldn't locate a PN)

[pablolizarraga]

I haven't installed it yet, but I'm pretty sure the size is correct: 52mm OD, 35mm ID, 22mm wide. I'll also find out if it really is just press old out, press new in.

Did replacing the bearing work out?


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[SJorge3442]

May econ light came on today on my 3.0 and now I have no air. It wasnt great before and a couple weeks ago I added a small can of 134 since the gauges were reading low. When I filed a few weeks ago, I noticed a green oil (maybe dye) which was on the gauge quick connect. Looking at these pictures, it looks just like the internals of your compressor - does this mean my compressor is toast or is the green substance normal system oil?

[cschuster]

May econ light came on today on my 3.0 and now I have no air. It wasnt great before and a couple weeks ago I added a small can of 134 since the gauges were reading low. When I filed a few weeks ago, I noticed a green oil (maybe dye) which was on the gauge quick connect. Looking at these pictures, it looks just like the internals of your compressor - does this mean my compressor is toast or is the green substance normal system oil?

Oh man that sucks. It’s been 90+ in KY for a month now. Glad the TTS has a well functioning Ac system :)

There’s a couple things in the Ac lines. Refrigerant (green), obviously, but also oil (clear) that lubes the compressor. Dye would depend on who worked on the car in its life.

You’ve either got a leak somewhere, or more likely, the compressor is bad.

[Turbo510]

Did replacing the bearing work out?

I've procrastinated on that job, but the heat is coming and then I'll have to do it (wife won't be in the car without AC!).

[SJorge3442]

Oh man that sucks. It’s been 90+ in KY for a month now. Glad the TTS has a well functioning Ac system :)

There’s a couple things in the Ac lines. Refrigerant (green), obviously, but also oil (clear) that lubes the compressor. Dye would depend on who worked on the car in its life.

You’ve either got a leak somewhere, or more likely, the compressor is bad.

So the light comes on and the AC stop working at strange moments. I can drive 80 miles with no issues and decently cold air, other times, 5 minutes into a drive it throws the ECON light. Only a start-restart of the motor seems to make it work again. Going off your statement, it seems like the refrigerant is green, so maybe I don't have an issue (yet at least). I'm gonna call up a local shop I trust to see how much they want for an EVAC/Fill of my system. Totally need to get this settled cause this damn leather interior takes forever to cool down with half ass AC lol.

[pablolizarraga]

I'm gonna call up a local shop I trust to see how much they want for an EVAC/Fill of my system.

No codes? Why not try one of those A/C cans first? They’re about $50 and stores currently offering gift card promotions; plus returning empty can you get $10 back. Though, curious to see though how much they quote for a evac/fill.

As for me, since my compressor grenaded itself, I’m considering purchasing A/C kit from discountacparts.com $440 for compressor, dryer, orifice tube, PAG oil, and o-rings.


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[SJorge3442]

No codes? Why not try one of those A/C cans first? They’re about $50 and stores currently offering gift card promotions; plus returning empty can you get $10 back. Though, curious to see though how much they quote for a evac/fill.

As for me, since my compressor grenaded itself, I’m considering purchasing A/C kit from discountacparts.com $440 for compressor, dryer, orifice tube, PAG oil, and o-rings.


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So I had put a can in and it got me up to the pressure I should of been at that day. Somewhere in the 40-45psi range on the low side. Im not sure how accurate the gauge is though. The air was better than before, but not great. Then on another day I added a little bit more 134a since the pressure was reading lower that day (Again, according to ambient temps) thats when I think it may have been a little over charged (?) since my HVAC was throwing a stinky smell through the vents, thus resulting in me relieving a little of the pressure.

Its my understanding that an evac will help pull any moisture out of the system as well that may have worked its way in over the years, right?

[pablolizarraga]

Not sure if evacuating the system is same but, putting the system under a vacuum for 15-30min will remove moisture and also reveal if there are any leaks. Your ECON light has not go on by itself while running the A/C? If it has, there’ll be codes.



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[pablolizarraga]

Went with this kit as it also includes the condenser (one less thing to flush) https://www.discountacparts.com/Audi...~82562_CK.html

The only other thing I would add to the part list of this thread is the oil cooler seal/o-ring (038117070A); not to be confused with the oil cooler gasket.

[SJorge3442]

Not sure if evacuating the system is same but, putting the system under a vacuum for 15-30min will remove moisture and also reveal if there are any leaks. Your ECON light has not go on by itself while running the A/C? If it has, there’ll be codes.



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Yeah vacuum and evac are basically the same. You're supposed to evac then pull a vacuum so that you dont let the 134A out into the atmosphere. Also, my Econ light has come on by itself. I probably have codes, but no way to read them as I don't have a VCDS cable any longer. Another reason why I was going to let a shop check it out.

[imnuts]

No codes? Why not try one of those A/C cans first?

It's very easy to overfill the system with just the can, and the high pressure sensor is very sensitive, at least in my experience. So a few grams over on the registrant level and it'll shut everything down.

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[SJorge3442]

It's very easy to overfill the system with just the can, and the high pressure sensor is very sensitive, at least in my experience. So a few grams over on the registrant level and it'll shut everything down.

Sent from my Pixel 2 XL

Yeah I remember reading this somewhere and I'm pretty sure I made a mistake and just need the system to be properly balanced. You were having serious AC problems before right? What was it that was causing the issue?

[imnuts]

I still have a partial issue, but the primary problem was that the compressor was bad. I had dye put in and the only leak that was found was at the compressor input shaft. It's worlds better than before, but if I park in the sun, or it's weather like we're currently having, it takes a long time to cool off. The condenser is also shot and needs to be replaced, but I'm not sure if I want to spend the money to fix it since it works 90% of the time. If I spray/soak the condenser with some water quick, it's enough to pull some heat out of the system and it helps band-aid it at the moment.

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[DarkoNova]

Man, I really hope my refrigerant is just low, but there's no visible leaks anywhere.

I reeeeeally hope I don't need a new compressor....

[Turbo510]

I replaced that pulley bearing over the weekend, but since I did it with the compressor installed, I pulled the whole carrier assembly off (coolant and power steering cooler lines disconnected, but not the AC hoses). The $52 triple-pin tool and Harbor Freight impact wrench zipped that drive plate right off. Next, the pulley came off without much effort, and boy the bearing was awful. I was able to get the old bearing out, and new one in, using a large socket to drive against the outer race, using a mallet. The only problem that I ran into was the PS cooler hoses; too old and dry to seal with just clamps, so after draining the reservoir and cleaning the pipes and inside of the hoses, used Permatex Silicone sealant. I've had to do this before on my B5, which had continual PS hose leakage until using the Silicone. Technique is to apply it to the tube right behind the barbed end, so when the hose is pushed on, no sealant gets inside to contaminate the system.

[Turbo510]

Here's a photo of the bearing as it looked after removing it from the pulley. Notice that the shield is off and plenty of balls have left the grooves. Caught in the nick of time!

[DarkoNova]

Did that fix your AC?

My compressor doesn't make any noise, so I don't think my bearing is bad. Or it is and it already destroyed itself.......

[Turbo510]

It fixed one problem; now I can run the compressor. But the pressure was low and I'm thinking of now just having a shop do the leak-test, evac and refill, plus any thing else that's found wrong. I added R134a until my can was empty, but the low-side pressure gauge on that auto store dispenser never got into the normal range. The evaporator supply pipe (smaller one) is getting somewhat cold, the discharge one should also but isn't.

If your compressor's hub plate rotates with the pulley, then the compressor is turning. You can easily reach down and grab the pulley; there shouldn't be any wiggle (I don't mean rotation) to it if the bearing is good.

Update: It needed more refrigerant, now the cabin air is plentifully cool even though outside it is 103F. Autozone loaned me a gauge set, first time I've used one in ages. I also looked up the appropriate low and high side pressures relative to ambient temperatures, and found that the system needed still more R134a. I added the refrigerant until both evaporator pipes felt equally cold at the firewall coupling, verified the pressures were in the ballpark, and have been using the AC for about a week. Initially, before changing the pulley bearing, static (non-running) pressure was very low, only 15 PSI, so I don't yet know if there was/is a leak or not. The AC pulley is now absolutely silent, which the whole motor pretty much is- the timing belt pulleys, coolant pump, and power steering pump are all under 6 months old.