Author Topic: A6 Compressors  (Read 613 times)

Offline Dan LeBlanc

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A6 Compressors
« on: June 15, 2017, 01:17:20 PM »
I don't think it's just me, but I've been hearing not so great things about the remanufactured A6 compressors.  Some have gone through several before finding a good one.

Long story short, my remanufactured A6 on my 70 (according to the previous owner's shop invoice) was installed in 2013 and is now making a growling noise.  Somewhat like a power steering pump low on fluid with a deeper tone.

So, it's not a matter of if it fails, it's a matter of when.  I'm getting cold air now and everything is working, but, when that day comes that the compressor fails, I'd like to repair once and be done with it.  Plan is to remove the evaporator and condenser and have them flushed professionally at a specialist.  Send the POA out to be reconditioned by Classic Auto Air, replace the drier, expansion valve, hoses, and compressor.  The compressor seems to be the weak link in the chain.

I want to charge with R-12 and of course, 525 mineral oil, but I only want to do it once.  How do I get rid of that weak link?  I've thought of everything from low mileage, used original, to NOS, to Pro6ten.  Pro6ten has been ruled out because of the slightly different location for the lines on the rear creating issues clearing the air cleaner although it looks like it may have been a good replacement.

So, I'm looking for ideas on how to make the system as good as new with no weak links.
Dan LeBlanc - CLC # 27657
1970 DeVille Convertible
1953 Series 62 Sedan (Parts Car)
1953 Fleetwood (Project Car)
2004 Deville

Online "Cadillac Kid" Greg Surfas 15364

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Re: A6 Compressors
« Reply #1 on: June 15, 2017, 02:39:56 PM »
Dan,
Most of the compressors fail due to oil starvation. The noise (most likely) you hear is the compressor running low on oil.  In ALL refrigeration systems the oil mixes and circulates with the refrigerant and when refrigerant leaks (usually via the infrequently run compressor) out the front seal it carries oil with it.  It is important to replace the oil when you replace refrigerant.  What kills the majority of the "bad" compressors is incorrect oil replacement in the correct amounts to the correct devices, and a failure to properly lubricate the front seal before starting and charging the system.  It is important that we know all of the compressor's components and their operation.  Incorrect charging can actually blow all the oil out of the compressors lubrication system, leading of course to early failure.
Try adding 3 or 4 ounces of oil to your compressor and see if the noise does not go away.
Greg Surfas
Cadillac Kid-Greg Surfas
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

Offline Dan LeBlanc

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Re: A6 Compressors
« Reply #2 on: June 15, 2017, 03:54:03 PM »
I did add a 2oz charge. Perhaps another 2oz may not hurt?

The work was all done before I got the car. High and low pressures are textbook. Air is cold for now.

It's discouraging that I have to pull it all apart at some point when the previous owner spent way too much money for a repair that didn't last.

The only way I'll know for sure is to pull the evaporator and condenser, have them flushed, replace the lines for safety sake, basically restore to as new.
Dan LeBlanc - CLC # 27657
1970 DeVille Convertible
1953 Series 62 Sedan (Parts Car)
1953 Fleetwood (Project Car)
2004 Deville

Offline Scot Minesinger

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Re: A6 Compressors
« Reply #3 on: June 15, 2017, 04:39:26 PM »
Dan,

The last three A6 compressors have been bad - all clutch related (it drags or is permanently engaged).  It is very important as Greg wrote to add oil as per the manufacturer's instructions - to each component.  I have to recover and change the third compressor now.  It is a convertible so not very critical - if it is 100'F and sunny and you see my 1970 DVC drive by with top up call the police - it is stolen.  A/C is ice on that rainy summer afternoon for me.

Yes of course if this was the last compressor on earth, I could maybe fix it, but not going to unless it happens on the next one.

You wonder why China is so successful infiltrating the American market, just a matter of time until they start remanufacturing A6 compressors just as low quality, but cheaper.
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

Online "Cadillac Kid" Greg Surfas 15364

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Re: A6 Compressors
« Reply #4 on: June 15, 2017, 04:40:28 PM »
Dan,
You can add the oil while the system is under pressure woith the proper device.
Greg Surfas
Cadillac Kid-Greg Surfas
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

Offline Dan LeBlanc

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Re: A6 Compressors
« Reply #5 on: June 15, 2017, 05:33:20 PM »
I'll add a bit more oil and see what happens. Easy enough to do.

From my understanding, if I flush everything out, upon reassembly, I add oil in the proper amounts listed in the shop manual to each of the components. I'm assuming from Scot's post that is the correct procedure.

I did notice that the add oil sticker was still on the sump drain plug on the compressor.  Im hoping they added oil through the suction side of the compressor and let it sit clutch side down for the 10 minutes most of the directions say.
Dan LeBlanc - CLC # 27657
1970 DeVille Convertible
1953 Series 62 Sedan (Parts Car)
1953 Fleetwood (Project Car)
2004 Deville

Online "Cadillac Kid" Greg Surfas 15364

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Re: A6 Compressors
« Reply #6 on: June 15, 2017, 07:09:57 PM »
Dan,
The oil sump (the bottom bulge with the plug in it) is on the "high" side of the compressor.  Pouring oil into the suction port with the compressor "dormant" will just accumulate and wait for refrigerant flow to distribute it where it needs to be.  The proper way to add oil to an operating compressor is with a pressurized transfer unit, so the oil enters the suction line along with refrigerant.  Slugging liquid, be it refrigerant or oil is also a great way to destroy a compressor.  It knocks the reed valves out and the compressor quits pumping.
Greg Surfas
Cadillac Kid-Greg Surfas
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

Offline TMoore - NTCLC

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Re: A6 Compressors
« Reply #7 on: June 16, 2017, 09:22:05 AM »
Scott -

I am just curious - why would you replace a compressor for a clutch problem?  Most of my A-6 issues have been clutch related, but replacing and spacing the clutch is pretty quick task, and does not involve opening up the system.

Tod

Offline Scot Minesinger

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Re: A6 Compressors
« Reply #8 on: June 16, 2017, 11:10:53 AM »
Tod,

Thanks if it is easy, maybe will do that instead.  The hassle of changing a compressor is easy, but still have to freight on the warranty there and back.

This is "new" and under warranty - works great (cools well), just will not shut off completely.
Fairfax Station, VA  22039 (Washington DC Sub)
1970 Cadillac DeVille Convertible
1970 Cadillac Sedan DeVille
1970 four door Convertible w/Cadillac Warranty

Online "Cadillac Kid" Greg Surfas 15364

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Re: A6 Compressors
« Reply #9 on: June 16, 2017, 11:58:16 AM »
Scott,
The compressor shaft is turning, the clutch is not making noise.  Did you think about the possibility of "thermal cycling" in the refrigeration system?
Greg Surfas
Cadillac Kid-Greg Surfas
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

Offline R S Steven

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Re: A6 Compressors
« Reply #10 on: June 16, 2017, 06:01:07 PM »
Hi All,
The last I new the A6 was still in production by Alma Products.  They took over production when Harrison stopped production.  You may want to give them a call.  I bought one 10+ years ago from a place in AZ and installed it on my 59 in place of the A5.

Alma Products Company
2000 Michigan Ave
Alma, MI 48801

www.almaproducts.com
E: Joellorenzo@almaproducts.com
P: 989-463-1151
F: 1-800-457-2719

http://www.almaproducts.com/Transtar.ALMA/media/ALMA-Media/Products/ac%20compressors/A6-Brochure-(7).pdf


Cheers,
Bob

Offline bcroe

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A6 Compressors
« Reply #11 on: June 16, 2017, 06:07:55 PM »
I have repaired a lot of A6 and R4 clutches, usually failed idler bearing.  Would never
mess with a good compressor, that just had a clutch problem. 

Bruce Roe

Offline Dan LeBlanc

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Re: A6 Compressors
« Reply #12 on: June 18, 2017, 08:30:32 AM »
This is the noise I've been experiencing. Adding oil made no difference.

https://youtu.be/M8AZhtmHvSg
« Last Edit: June 18, 2017, 09:25:21 AM by Dan LeBlanc »
Dan LeBlanc - CLC # 27657
1970 DeVille Convertible
1953 Series 62 Sedan (Parts Car)
1953 Fleetwood (Project Car)
2004 Deville

Online "Cadillac Kid" Greg Surfas 15364

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Re: A6 Compressors
« Reply #13 on: June 18, 2017, 08:57:01 AM »
Glad it worked Dan.  A lot simpler than changing compressors.
Greg Surfas
Cadillac Kid-Greg Surfas
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

Offline TJ Hopland

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Re: A6 Compressors
« Reply #14 on: June 18, 2017, 09:25:20 AM »
I assume ON was a typo for NO as in no difference?

What RPM was that?   Didn't seem like idle which is where most of us would used to be the engine speed when we are standing in front of the car with the hood open listing to noises. 
StPaul/Mpls, MN USA

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Offline Dan LeBlanc

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Re: A6 Compressors
« Reply #15 on: June 18, 2017, 09:28:04 AM »
Thanks for picking up on the typo. My phone's autocorrect does strange things sometimes.

This was between high idle and curb idle.  I'd guesstimate somewhere between 1200 and 1300 RPM. At curb idle the noise is still there though.
« Last Edit: June 18, 2017, 09:38:12 AM by Dan LeBlanc »
Dan LeBlanc - CLC # 27657
1970 DeVille Convertible
1953 Series 62 Sedan (Parts Car)
1953 Fleetwood (Project Car)
2004 Deville

Offline Dan LeBlanc

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Re: A6 Compressors
« Reply #16 on: June 18, 2017, 09:52:33 AM »
Thankfully I have the 8 track to drown it out

https://youtu.be/Qo_ivd9Z96w
Dan LeBlanc - CLC # 27657
1970 DeVille Convertible
1953 Series 62 Sedan (Parts Car)
1953 Fleetwood (Project Car)
2004 Deville

Online "Cadillac Kid" Greg Surfas 15364

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Re: A6 Compressors
« Reply #17 on: June 18, 2017, 10:09:59 AM »
Dan,
Sorry I guess that was wishful thinking in my last response. How much oil did you add and where did you add it. It can take a while for the oil to actually get where it is supposed to be.  Also, what is the discharge pressure? Frequently a high discharge pressure caused by air in the system can lead to discharge valve noise.
Greg Surfas
Cadillac Kid-Greg Surfas
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

Offline Dan LeBlanc

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Re: A6 Compressors
« Reply #18 on: June 18, 2017, 10:27:33 AM »
Hi Greg.

I added the oil through the suction port - 1 4 ounce can.  Let it run for about 10 minutes before filming.  Last time I had a set of gauges on it was last weekend. Was about 86F here. Low side was 30psi. High side was 165psi. Vent temperature that day was 51F. That was after a drive of about 1/2 hour. The system seems to be working, just very noisily

My refrigerant as 12a (that's what I can buy legally here without smuggling R12 cans across the border). 

I was cautiously optimistic that it would help, but Murphy's law is never on my side.

Hopefully I'll get the rest of the summer out of it.

Brings me back to my original question as to what my best compressor option is. Perhaps send this one out to a reputable rebuilder? Reinstall after flushing all components, add 525 mineral oil, get the system in a vacuum state, and recharge with R12 Stateside before driving back across the border. Im only 35 miles from the Maine border thankfully.
« Last Edit: June 18, 2017, 10:35:39 AM by Dan LeBlanc »
Dan LeBlanc - CLC # 27657
1970 DeVille Convertible
1953 Series 62 Sedan (Parts Car)
1953 Fleetwood (Project Car)
2004 Deville

Online "Cadillac Kid" Greg Surfas 15364

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Re: A6 Compressors
« Reply #19 on: June 18, 2017, 02:15:06 PM »
Dan,
Forgive me if you previously mentioned having R-12"A" in your system.  "R-12A" as you know is a mixture of propane and butane. Both make excellent refrigerants, and have een used for over 100 years as such.  The also make one of the best possible SOLVENTS one could imagine with any Hydrocarbon substance such as Mineral oil.  That noise in your compressor IS due to a lack of lubrication and what is happening is that the Mineral oil does not mix and freely circulate with the refrigerant and what oil does find its way around the system is diluted and does not lubricate either the compressor bearings nor the shaft seal as intended.  R-12A and the numerous other "drop-ins" that came out are a primary cause for the seeming "explosion" of compressor failures that the industry has experienced. The A-6 compressor was designed and refined around R-12 and Mineral oil as the working fluids. Metallurgy, chemical actions and reactions were all studied and components modified as required to meet those chemicals properties.
IF you want to do this once and be able to "walk away" for an extended period you seem to be on the right track.
It is hard to tell if the compressor's bearing surfaces have been damaged by the diluted lubrication, and just how much the refrigerant hoses have been "softened" by the Propane/Butane mix.  What is in order for a permanent fix would seem to be the following;
1. Re[placement A-6 compressor (I would get a Delco rebuilt http://www.rockauto.com/en/catalog/cadilla,1976,deville,8.2l+500cid+v8,1409374,heat+&+air+conditioning,a
Add 5-1/2 oz of mineral oil in through the drain plug at the compressor's oil sump, and with the compressor un the horizontal position, rotate the shaft (via the clutch hub) several dozen times to get oil circulating in the compressor.
2. remove and flush the evaporator and condenser thoroughly to remove all traces of oil and residue.
3. Have new hoses made
4.During installation, ad the FSM suggested quantities of Mineral Oil at the locations suggested.
Re assemble, leak check under pressure, and then evacuate using a quality vacuum pump for at least an hour.
5.with the system under vacuum charge a couple of pounds of R-12 (liquid) in the high side.  It will go to the condenser as intended.
6. Start the system and finish charging refrigerant in the vapor form via the low side till the site glass is clear.
You asked for the correct way to do it and these are my suggestions.
Greg Surfas
Cadillac Kid-Greg Surfas
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-