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Old 07-19-2020, 11:39 PM   #1
Pow
Scooby Newbie
 
Member#: 54811
Join Date: Feb 2004
Location: Southeast PA
Vehicle:
2006 Baja
Atlantic Blue Pearl

Default Some AC troubleshooting and repair tips, compressor clutch

Dusting off the old account to share some experiences here. I couldn't find a write up with this info in my web searches so thought it best I add to the collective internet hive-mind. Give the next guy a jump start on wrenching.

2006 Baja, almost 300k on the clock. Love this thing but recently (last year or so) the AC has been giving me some fits. I'm only going to go into detail about what I learned today, but I'll still give some history. Started that with after a major service to replace head gaskets which required an engine drop, the seals (still 2006 rubber I guess) on the AC compressor fittings were leaking. Fixed that and then started trying DIY recharge systems. Back and forth, never really trusted I was where I should be with the refrigerant. A couple months ago took it to a local shop for a proper recharge. They found me low and correctly charged up the system, they also added a leak detection dye just in case. They said it wasn't putting out exactly the temp that it should in their testing (at max should be 40 degrees Fahrenheit below ambient I think?) but said it could be that because the test was while parked with only fan airflow through the cooling grill it may not have had optimal performance, or maybe it was something else that would require more digging. It was cooling enough that I was happy with the results, and in the few times I've used it during the limited travel of the pandemic it has been fine.

Until the recent heat in SE PA and a few 15+ minute drives. Then all of a sudden after no issues cooling the air from the vents started blowing humid with a slight wet/musty smell, and steadily began to warm up. I stopped to check under the hood and the compressor wasn't spinning.

The troubleshooting starts...

* Is the clutch getting voltage?
Started here because it was an easy check. Disconnected the lead going to the compressor and measured volts coming out of that lead to ground. Was seeing operating (about 14V) voltage. Told me all the switches leading to the compressor were in the proper state for it to run.

* Is the clutch coil OK?
Tested the connector that is a part of the compressor twice, both with the system "cold" and then when it was warm and in "failed" state. First test each time was continuity to ground, and that showed about 5 ohms each time. I assume this is probably about right for the coil but didn't try to look up a spec. I checked to see how many amps it would draw if I tested between the compressor side of the plug and battery positive, saw about 2.5A.

On initial amperage tests I didn't notice this but eventually I spotted the ever so slight movement of the clutch plate when testing. I could then easily reproduce that by disconnecting/reconnecting the lead to the compressor. One time the compressor even engaged again. This really zeroed me in on the issue, the clutch was slipping.

* Is the clutch gap in spec?
Didn't have any feeler gauges (or if I did I have no idea where they are) so went out and picked up a simple set for $5 at Harbor Freight. (feeler gauges can't kill me, right?) The 0.0300" gauge was pretty easy to get in, the 0.0320" gauge would go in but tight. So now I know what the gap is, tried to find the Subaru spec. From unofficial info I found it looks like it should be... holy crap! 0.0177-0.0059"?!? Well there is the problem. There had also been a good bit of rusty looking dust building up in the area, which I now assume is from the AC clutch when slipping.

So on to the repair!

Did some online research and found info on working on the clutch. First trick was to get out the bolt (10mm head, of course) from the center of the clutch. For this I threaded a bolt (M5-0.8) into one of the holes in the clutch plate face and used a wrench for leverage between that bolt and the ratchet in the center bolt. This allowed me to get the bolt loose and out. NOTE #1: I DO NOT RECOMMEND THIS METHOD. It worked, but what I should have done is picked up a loaner tool like this which would have allowed me to leverage all three clutch plate pull points.

Next was to pull the plate itself. One of the videos I found:
showed using M5-0.8x40mm bolts into the three clutch plate pull holes and just incrementally tightening them to "push" the plate back off the splined shaft. I figured this was safe as where these holes were was not the mating surface of the clutch. It worked (I used 30mm long bolts) but the bolts I had seemed to be a bit soft as some started to bend. Which brings me to NOTE #2: I DO NOT RECOMMEND THIS METHOD. While the bolts weren't going on the clutch mating surface, as they bent one did get dangerously close to going into the bearing race of the pulley. I probably should have used something like this or maybe this, although one AC clutch service video:
showed how you could improvise using the aforementioned clutch holder tool and a bolt with washers, which I believe would probably be OK. But if you're out to get a loaner holder tool, why not just grab the puller as well?

The plate finally freed and of course the shims in the middle dropped right through the engine bay to the ground. I was in my paved driveway so no worry, but I'd suggest throwing something underneath the engine if there is any chance they could drop somewhere and get lost. I had two shims, if my digital caliper is to be trusted they measured out at 0.0110" and 0.004". So to close up the gap to within spec I left both out on reassembly.

Took the time to wipe both the clutch mating surfaces with some brake cleaner on a rag. Not sure if I should have done this but both were dusty and being I needed to remove all shims things are obviously quite worn so I am ordering up a replacement kit anyway.

Reinstalling (w/o shims) was a bit of fun. Using a mallet to hit the face of the clutch plate I was able to get it far enough in for the center bolt to get a few turns of bite. Knowing I was risking stripping the bolt, or shaft, or snapping the bolt in the shaft I proceeded to use the bolt to snug the plate back on to the shaft. NOTE #3: I think you know where this is going. In the future I'd pick up a loaner installer tool at the same time I picked up the tools to hold and remove the plate. Again needed to rely on a bolt threaded into one of the plate holes for leverage with a wrench. (See note #1.)

Once I felt I had things properly tightened I checked the gap again. I was now at about 0.0080" and within what I believe to be the Subaru spec.

Out for a long drive and the AC worked without fail. Even tried a couple times turning the AC on while the engine was at high RPM, which I think would provide the most likely scenario for the clutch to slip, and it still engaged. When my replacement parts come in I'm not sure if I'll immediately install them or shelve them to be ready for a later date. Right now things look to work well and I'm not putting many miles on at the moment anyway, certainly no long trips like where the failure used to occur most often.

Hope all this can be helpful to someone in the future!
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Last edited by Pow; 07-20-2020 at 09:47 AM.
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Old 07-20-2020, 12:58 AM   #2
GalaxyWide
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Member#: 383291
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Chapter/Region: MWSOC
Location: Great White North
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2004 Forester XT
Cayenne Red

Default

Thanks for posting this, good write-up! This issue seems to be somewhat common on higher mileage subies, I've had to do it once so far and if I lived someplace warmer (and drove more often) I'm sure I'd have done it again by now.

Great advice to get the correct pulling tools, I mangled my clutch plate and had to source an entire used compressor assembly to pull one off of.
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Old 08-02-2020, 08:12 PM   #3
1hwy0city
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Join Date: Jun 2020
Default

Quote:
Originally Posted by Pow View Post
Dusting off the old account to share some experiences here. I couldn't find a write up with this info in my web searches so thought it best I add to the collective internet hive-mind. Give the next guy a jump start on wrenching.

2006 Baja, almost 300k on the clock. Love this thing but recently (last year or so) the AC has been giving me some fits. I'm only going to go into detail about what I learned today, but I'll still give some history. Started that with after a major service to replace head gaskets which required an engine drop, the seals (still 2006 rubber I guess) on the AC compressor fittings were leaking. Fixed that and then started trying DIY recharge systems. Back and forth, never really trusted I was where I should be with the refrigerant. A couple months ago took it to a local shop for a proper recharge. They found me low and correctly charged up the system, they also added a leak detection dye just in case. They said it wasn't putting out exactly the temp that it should in their testing (at max should be 40 degrees Fahrenheit below ambient I think?) but said it could be that because the test was while parked with only fan airflow through the cooling grill it may not have had optimal performance, or maybe it was something else that would require more digging. It was cooling enough that I was happy with the results, and in the few times I've used it during the limited travel of the pandemic it has been fine.

Until the recent heat in SE PA and a few 15+ minute drives. Then all of a sudden after no issues cooling the air from the vents started blowing humid with a slight wet/musty smell, and steadily began to warm up. I stopped to check under the hood and the compressor wasn't spinning.

The troubleshooting starts...

* Is the clutch getting voltage?
Started here because it was an easy check. Disconnected the lead going to the compressor and measured volts coming out of that lead to ground. Was seeing operating (about 14V) voltage. Told me all the switches leading to the compressor were in the proper state for it to run.

* Is the clutch coil OK?
Tested the connector that is a part of the compressor twice, both with the system "cold" and then when it was warm and in "failed" state. First test each time was continuity to ground, and that showed about 5 ohms each time. I assume this is probably about right for the coil but didn't try to look up a spec. I checked to see how many amps it would draw if I tested between the compressor side of the plug and battery positive, saw about 2.5A.

On initial amperage tests I didn't notice this but eventually I spotted the ever so slight movement of the clutch plate when testing. I could then easily reproduce that by disconnecting/reconnecting the lead to the compressor. One time the compressor even engaged again. This really zeroed me in on the issue, the clutch was slipping.

* Is the clutch gap in spec?
Didn't have any feeler gauges (or if I did I have no idea where they are) so went out and picked up a simple set for $5 at Harbor Freight. (feeler gauges can't kill me, right?) The 0.0300" gauge was pretty easy to get in, the 0.0320" gauge would go in but tight. So now I know what the gap is, tried to find the Subaru spec. From unofficial info I found it looks like it should be... holy crap! 0.0177-0.0059"?!? Well there is the problem. There had also been a good bit of rusty looking dust building up in the area, which I now assume is from the AC clutch when slipping.

So on to the repair!

Did some online research and found info on working on the clutch. First trick was to get out the bolt (10mm head, of course) from the center of the clutch. For this I threaded a bolt (M5-0.8) into one of the holes in the clutch plate face and used a wrench for leverage between that bolt and the ratchet in the center bolt. This allowed me to get the bolt loose and out. NOTE #1: I DO NOT RECOMMEND THIS METHOD. It worked, but what I should have done is picked up a loaner tool like this which would have allowed me to leverage all three clutch plate pull points.

Next was to pull the plate itself. One of the videos I found:Subaru A/C Compressor Clutch - YouTube showed using M5-0.8x40mm bolts into the three clutch plate pull holes and just incrementally tightening them to "push" the plate back off the splined shaft. I figured this was safe as where these holes were was not the mating surface of the clutch. It worked (I used 30mm long bolts) but the bolts I had seemed to be a bit soft as some started to bend. Which brings me to NOTE #2: I DO NOT RECOMMEND THIS METHOD. While the bolts weren't going on the clutch mating surface, as they bent one did get dangerously close to going into the bearing race of the pulley. I probably should have used something like this or maybe this, although one AC clutch service video:Fixing car air conditioning that dies after a few minutes on hot days - YouTube showed how you could improvise using the aforementioned clutch holder tool and a bolt with washers, which I believe would probably be OK. But if you're out to get a loaner holder tool, why not just grab the puller as well?

The plate finally freed and of course the shims in the middle dropped right through the engine bay to the ground. I was in my paved driveway so no worry, but I'd suggest throwing something underneath the engine if there is any chance they could drop somewhere and get lost. I had two shims, if my digital caliper is to be trusted they measured out at 0.0110" and 0.004". So to close up the gap to within spec I left both out on reassembly.

Took the time to wipe both the clutch mating surfaces with some brake cleaner on a rag. Not sure if I should have done this but both were dusty and being I needed to remove all shims things are obviously quite worn so I am ordering up a replacement kit anyway.

Reinstalling (w/o shims) was a bit of fun. Using a mallet to hit the face of the clutch plate I was able to get it far enough in for the center bolt to get a few turns of bite. Knowing I was risking stripping the bolt, or shaft, or snapping the bolt in the shaft I proceeded to use the bolt to snug the plate back on to the shaft. NOTE #3: I think you know where this is going. In the future I'd pick up a loaner installer tool at the same time I picked up the tools to hold and remove the plate. Again needed to rely on a bolt threaded into one of the plate holes for leverage with a wrench. (See note #1.)

Once I felt I had things properly tightened I checked the gap again. I was now at about 0.0080" and within what I believe to be the Subaru spec.

Out for a long drive and the AC worked without fail. Even tried a couple times turning the AC on while the engine was at high RPM, which I think would provide the most likely scenario for the clutch to slip, and it still engaged. When my replacement parts come in I'm not sure if I'll immediately install them or shelve them to be ready for a later date. Right now things look to work well and I'm not putting many miles on at the moment anyway, certainly no long trips like where the failure used to occur most often.

Hope all this can be helpful to someone in the future!
Thanks for the thorough write up. I put in a rebuilt compressor expansion valve and condenser and I'm having warmer Air at idle plus higher pressure on the low side. It was a cheaper rebuilt compressor so I will check the clutch play

Last edited by 1hwy0city; 08-02-2020 at 08:32 PM.
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Old 08-30-2020, 03:01 PM   #4
R2-RO
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Member#: 518198
Join Date: Aug 2020
Location: Campeche, México
Vehicle:
2014 Impreza
Black

Default AC Compressor noise Subaru Impreza 2014

Hi, I have a Subaru Impreza Ltd 2014, when a turn on the AC compressor makes a noise, like a wind up toy but louder, I went with a AC technician, but he said that is the compressor and I have to change it and the condenser How can I discard that just is the pulley or clutch? I don't want change all the system (it's a lot of money for me) if the reason is something simple, I uploaded a video on YouTube with my issue.

https://youtu.be/ErkfLcEtlfA
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Old 09-24-2020, 06:46 PM   #5
Lug_Nuts_23
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Member#: 506272
Join Date: Sep 2019
Location: Kansas City area
Vehicle:
2002 WRX Sedan
Silver

Default

Thanks for the writeup!

Hmmm this sounds a lot like what could be happening to me. Yesterday the A/C worked. Today it didn't. No "clunk" from under the hood to tell me it engaged when I pressed the switch. The switch inside still lights up when pressed, and I tried switching two relays under the hood (A/C compressor and an identical-looking relay) and that made no difference either. The compressor is easy to spin by hand.

Previously, the air worked fine though it seemed like the compressor was clutching in and out a bit. I thought maybe someone overcharged the system so the compressor was automatically de-clutching to prevent icing up or excess force, but now that I've seen your post I see it could have just been slipping and re-engaging. Hmmm...I'll have to see if I can get some loaner tools to do the job.
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Old 09-25-2020, 09:36 PM   #6
Lug_Nuts_23
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Join Date: Sep 2019
Location: Kansas City area
Vehicle:
2002 WRX Sedan
Silver

Default

Quote:
Originally Posted by Pow View Post

Out for a long drive and the AC worked without fail. Even tried a couple times turning the AC on while the engine was at high RPM, which I think would provide the most likely scenario for the clutch to slip, and it still engaged. When my replacement parts come in I'm not sure if I'll immediately install them or shelve them to be ready for a later date. Right now things look to work well and I'm not putting many miles on at the moment anyway, certainly no long trips like where the failure used to occur most often.

Hope all this can be helpful to someone in the future!
What brand of replacement clutch are you using and where did you get it?

Thanks!
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Old 09-27-2020, 10:20 PM   #7
Pow
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Member#: 54811
Join Date: Feb 2004
Location: Southeast PA
Vehicle:
2006 Baja
Atlantic Blue Pearl

Default

Quote:
Originally Posted by R2-RO View Post
Hi, I have a Subaru Impreza Ltd 2014, when a turn on the AC compressor makes a noise, like a wind up toy but louder, I went with a AC technician, but he said that is the compressor and I have to change it and the condenser How can I discard that just is the pulley or clutch? I don't want change all the system (it's a lot of money for me) if the reason is something simple, I uploaded a video on YouTube with my issue.

https://youtu.be/ErkfLcEtlfA
From the video your clutch looks to be engaging properly (tough to tell if it is spinning 1:1 with the pulley) so you've got something else going on as opposed to what I experienced. I suppose it could be something with the clutch coil as a coil energizing at a high frequency could make a buzzing sound, but I can't say I would expect that to happen. Maybe with the car off jump 12v to the clutch coil input and see if it makes a buzzing or just closes the clutch? If no buzz then it probably has nothing to do with the coil, but if a buzz then you've got at least a part of your issue isolated. I'd advise putting this into a new thread if you haven't done so already, may help to get more eyes on it as you can tune the subject to your issue.

Quote:
Originally Posted by Lug_Nuts_23 View Post
What brand of replacement clutch are you using and where did you get it?

Thanks!
I didn't get anything special just something from a North America seller on eBay. This was the exact item I purchased: https://www.ebay.com/itm/263974322240 From what I can see it looks to be a proper replacement kit, I haven't needed to install it yet. (AC still working fine via the shims I removed.) My only complaint is it did take a few days from when the seller posted a tracking number (claimed "shipped") until when FedEx actually had it in their possession... not sure what was going on there but we are in unusual times. The coil tests out fine on a multimeter and all parts look correct so I've got no worries for if I need to install it... glad that since I found where my problem was that I have the parts on a shelf ready to go should it resurface.

But, did you test the electronics first? Coil pigtail from the compressor has continuity (with some resistance) to ground, and you get 12-14v on the lead heading to the compressor when it should be engaged? Don't order up a kit until you've tested out these points. See the "Is the clutch getting voltage?" and "Is the clutch coil OK?" sections of my original post.

Last edited by Pow; 09-27-2020 at 10:47 PM.
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Old 09-29-2020, 08:20 PM   #8
Lug_Nuts_23
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OK, thanks for the reply.

I'm looking into it/getting it looked into more thoroughly before buying any replacement parts.
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Old 04-22-2021, 10:23 PM   #9
cvedrick
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Silver

Wink

I myself recently replaced the elusive impresa clutch with an aftermarket one, everything went great until the end where i realized the difference between plate thickness on the original (worn down till the rivets parted, the plate was literally held on by 1 worn rivet) and the new one caused the clutch to lock up permanently.

Realizing that over its 165,000mi life it must have been "serviced" and shims must have been removed. I had to add more shims!

The 3 that came with the new clutch did nothing.

Of course being an un-supported repair Subaru had nothing as did the auto parts stores.

I found out through measuring and research that 1/2" x 3/4" shims worked fine and ended up getting these from amazon.

Shoulder-Shortening Shim Flat Washer, 18-8 Stainless Steel, 1/2" Bolt Size, 0.501" ID, .750" OD, 0.005" Thick (Pack of 50)

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Note that i had to add about 20 of these things to get the airgap large enough to work. You guys may want slightly thicker
ones.

Also fount that a small screwdriver helped install them, I put the shim over the tip via the hole then touched the tip to the upper canter of the shaft and slid the shim right on. Also found that being a low series SS the shims were magnetis and i could use my pick up magnet to easily remove a few. (if your working on Subarus that pickup mahnet is a lifesaver)

Last edited by cvedrick; 04-22-2021 at 10:28 PM.
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Old 04-28-2021, 09:41 PM   #10
bofh
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Join Date: Apr 2004
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Location: Houston, Tx
Vehicle:
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2004 WRB WRX (RIP)

Default Thank you!

Glad I saw this. I am having the opposite problem but it is worth a test. My post is over here. https://forums.nasioc.com/forums/sho...8#post46557508 Glad I saw this post.
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Old 06-04-2021, 10:33 AM   #11
tsolyankee
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Join Date: Aug 2008
Chapter/Region: South East
Location: Mebane, NC
Vehicle:
2003 Impreza WRX
Black & Blue

Default

Quote:
Originally Posted by cvedrick View Post
I myself recently replaced the elusive impresa clutch with an aftermarket one, everything went great until the end where i realized the difference between plate thickness on the original (worn down till the rivets parted, the plate was literally held on by 1 worn rivet) and the new one caused the clutch to lock up permanently.

Realizing that over its 165,000mi life it must have been "serviced" and shims must have been removed. I had to add more shims!

The 3 that came with the new clutch did nothing.

Of course being an un-supported repair Subaru had nothing as did the auto parts stores.

I found out through measuring and research that 1/2" x 3/4" shims worked fine and ended up getting these from amazon.

Shoulder-Shortening Shim Flat Washer, 18-8 Stainless Steel, 1/2" Bolt Size, 0.501" ID, .750" OD, 0.005" Thick (Pack of 50)

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Note that i had to add about 20 of these things to get the airgap large enough to work. You guys may want slightly thicker
ones.

Also fount that a small screwdriver helped install them, I put the shim over the tip via the hole then touched the tip to the upper canter of the shaft and slid the shim right on. Also found that being a low series SS the shims were magnetis and i could use my pick up magnet to easily remove a few. (if your working on Subarus that pickup mahnet is a lifesaver)
To hell with the magnet, you sir are a life saver, thank you!
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Old 07-19-2021, 03:24 PM   #12
Pow
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Member#: 54811
Join Date: Feb 2004
Location: Southeast PA
Vehicle:
2006 Baja
Atlantic Blue Pearl

Default

Quote:
Originally Posted by cvedrick View Post
I myself recently replaced the elusive impresa clutch with an aftermarket one, everything went great until the end where i realized the difference between plate thickness on the original (worn down till the rivets parted, the plate was literally held on by 1 worn rivet) and the new one caused the clutch to lock up permanently.

Realizing that over its 165,000mi life it must have been "serviced" and shims must have been removed. I had to add more shims!
Thanks for posting your info on this. The other day I believe my clutch slipped again so it might be time for me to finally install the kit I bought last year. As advised I'll order up some extra shims as well so I've got them ready.

Assuming there is no way for me to figure out before just how many shims I'd need to install, I'm thinking what I'd do is install plenty extra to start so the gap is excessive. Measure out the gap, figure out how much space in shims I need remove, pop the clutch back off, remove the excess shims that equate to how much I need to close up the clutch, then reinstall the clutch. Theory being I'll only need to remove/install the clutch twice! If you have too few shims on the first install you'll still be guessing at how many you need to add.
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