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GM A-6 Compressors, Rebuilt?

Chewed 71'er on Sat August 30, 2003 3:32 AM User is offline

Year: 1971
Make: Chevy Pickup
Model: C-10

I changed my pickup over to 134a last year, complete with a rebuilt, 134a rated compressor. The front seal went bad after only a year. Do these older A-6 compressors have problems in running the newer freons? I changed the polyol ester oil (from last year) over to PAG ISO150 this year. Hope it helps.

Mitch on Sat August 30, 2003 10:31 AM User is offline

A6 works just fine with 134a.

A lot of A6s with the carbon or ceramic face seals will throw a little oil on the hood and that is considered normal. The hard part is determining the difference between normal and abnormal. Normal will not have any refrigerant leakage, only a little oil. Abnormal will give a hit on an electronic leak detector, and eventually the system is low on gas.

The new GM double lip seal will also fit the A6 and should have zero leakage. It would be hard to tell what you have.

You leakage may be completely normal, or you just may have a bad seal due to poor workmanship or parts quality. Even good parts fail sometimes too so it just may be bad luck with that particular compressor.

Do you have more info on the size of the leak?

Anonymous on Tue September 30, 2003 12:59 PM User is offline

Here's some more feedback and a similar question. I have a 1969 el camino, I replaced the compressor (a6) because of water contamination. the old compressor never leaked one drop of oil. I have since purchased and installed three remanufactured compressors on this car. the first was purchased at autozone and remanufactured by I believe factory air. It leaked oil from the rear head o-ring, the second from the same remanufacturer leaked excessively at the main seal. the third and current is from napa by four seaons. it leaks from the main seal as well. This system was THOROUGHLY cleaned and flushed. new expansion valve, new poa, new condenser, new drier. Installation and evacuation have been meticulously performed. yet I have oil leakiing from the main seal. Granted it's not A-LOT but it is an unacceptable amount since it makes a MESS under the hood. Should I go to new gm compressor? I am really hoping to find a solution to this problem. you mentioned a new type of seal could you elaborate?

Thanks, KIRK

Mitch on Tue September 30, 2003 2:38 PM User is offline


I will elaborate on the seals later on today when I have more time.

In the meantime, for some background info, go to google and search on - Mechanical seal leakage in IMO pumps.

I can't seem to make the link work.

Edited: Tue September 30, 2003 at 3:10 PM by Mitch

Anonymous on Tue September 30, 2003 3:28 PM User is offline

Thanks for the reply and info Mitch.

I have some experience with ceramic mechanical seals in fire pump and high pressure domestic water applications. and yes we always accepted a very small amount of leakage. I just don't remember having a problem like this in the past with ANY of my vehicles using the a6.
I did some research on the net and found many sources to purchase a brand new ac delco a6 (delco p/n 15-2225) and some sources for the ceramic seal (p/n 15-2191) I could not find any info however on any other seal types, or whether or not the 15-2225 comes with the old or new seal type.

thanks again, kirk

Mitch on Tue September 30, 2003 9:44 PM User is offline

This is the story on shaft seals. They have to leak or they will go up in smoke in seconds. The real question is how much leakage is acceptable. The best seals have a leakage that is effectively invisible. Those are the ones that are said not to leak, but in truth they are leaking. That is why hermetic systems can last for 30+ years. No leaking shaft seals.

This is the official GM position on seal leakage in 2001 for a V5 with double lip seal:

"Do not change a shaft seal because of small amounts of oil found on an adjacent surface. The seal allows some oil to pass for lubrication purposes. Change the shaft seal when the following conditions exist:
1. A large amount of sprayed oil is found.
2. Actual refrigerant leakage is found using a J 39400-A or equal"

This is the GM position on seal leakage in 1978 on the instruction sheet for an A6 seal kit #15-210 or GM #6599114 using ceramic face seals:

"Compressor seals should be replaced only on the basis of actual refrigerant leakage as determined by test with a leak detector in good condition. They should not be changed because of an oil streak on the hood blanket unless there is an excessive amount of oil in the rest of the engine compartment."

More later.

Edited: Tue September 30, 2003 at 9:48 PM by Mitch

Mitch on Tue September 30, 2003 10:16 PM User is offline

I have lived with an A6 and shaft seal seepage/leakage since I bought my 69 Impala new 34 years ago and have driven it almost 400,000 miles. I am currently on my 3rd shaft seal (2nd replacement), and I have the oil streak on the hood.

Sometimes it leaks, sometimes it doesn't. I have seen it throw oil on the driver's inner fender in small droplets and then it goes away. The greatest amount of leakage always occured after I had pulled the compressor for some type of engine or AC maintenance, and added some oil just for insurance. Then it seems to get better after a while, as if there was too much oil in the sump. I really can't explain it completely, but except for the two seal changes, I would just let it leak until it stopped, loosely keeping track of the amount to make sure the compressor was not too low on oil.

GM Tech has indicated that the new GM double lip seal ACD# 15-30948, GM# 2724954 for HR6s and V5s will backfit into the A6, but I have not tried it. The advantage of the double lip seal is that it will probably have an acceptable leakage rate immediately after installation if the install is done correctly, and when it gets too high, it will be obvious. The disadvantage is that over the long run, it wears out the compressor shaft, which the mechanical face seal will not do.

This is a pic of the A6 mechanical face seal. The double lip seal will fit where the existing seal seat is at.

Edited: Tue September 30, 2003 at 10:17 PM by Mitch

Anonymous on Tue September 30, 2003 11:13 PM User is offline

thanks for all your time and info. I will check for refrigerant leakage and if i find none i will "run it" for a while and see what happens


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