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Moisture + R12 or R134a = Acid?

nyc951 on Mon September 19, 2005 8:50 AM User is offline

Hi:

Which refridgerant, R12 or R134a, has a tendency to create some sort of acid when it comes in contact with moisture?

Reason I ask is that my R-134a A/C system has a leak in it and I'm sure moisture has entered the system. The type of oil used is Ester and the leak occurred about a year ago. (I know, I know, but I've been busy).

What do you guys think? Thanks.

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'98 328i

Test Specimen on Mon September 19, 2005 9:16 AM User is offline

R-12 is the one that can react with moisture to form strong acids. The chlorine atom in the R-12 is less tightly bound to the refrigerant than the fluorines. R-134a does not have any chlorine, so does not react with moisture.

PredatorOmnivore on Tue September 20, 2005 1:10 PM User is offline

On the other hand, some R-134a systems use POE "oil" . POE is not a true "oil" that is non-polar. POE is hygroscopic. It sucks moisture out of the air. The wet POE doesn't lubricate well. The water in the POE corrodes AC parts.

If the system is at 0 psig. Pressurize it with Nitrogen, find and fix the leak. Replace the Receiver Dryer or Accumulator add back some "oil" and recharge.

Chick on Tue September 20, 2005 1:18 PM User is offlineView users profile

Quote
Originally posted by: PredatorOmnivore
On the other hand, some R-134a systems use POE "oil" . POE is not a true "oil" that is non-polar. POE is hygroscopic. It sucks moisture out of the air. The wet POE doesn't lubricate well. The water in the POE corrodes AC parts.



If the system is at 0 psig. Pressurize it with Nitrogen, find and fix the leak. Replace the Receiver Dryer or Accumulator add back some "oil" and recharge.

POE is hydroscopic, but PAG is much more hydroscopic than ester.. That is the reason for pulling a good vacuum to proper microns, and why you have disicant bags in the drier/accumulators ...Just my opinion though..

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

avx on Tue September 20, 2005 1:33 PM User is offline

I have a question that might fit in this thread: what to do about oil left inside the manifold hoses? It's going to absorb water and carry it into the system next time the gauges are used. This can be minimized if the gauge set is kept will all fitting tightened and valves shut, but that wouldn't be good for the seals, right? I know this is more of a concern, if any, for DIYers, who use their gauges infrequently.

nyc951 on Tue September 20, 2005 2:06 PM User is offline

So should I disconnect ALL of the components and flush out the old oil? I hope not!

I found the leak, which is a crack on one of the condensor's tubes. I imagine any kind of moisture that got in through the crack would be minimal, and since the condensor will be replaced, will I be ok using the oil that's in the system?

Is Ester oil the same as POE?

Thanks guys.

-------------------------
'98 328i

TRB on Tue September 20, 2005 2:24 PM User is offlineView users profile

Quote
Originally posted by: PredatorOmnivore
On the other hand, some R-134a systems use POE "oil" . POE is not a true "oil" that is non-polar. POE is hygroscopic. It sucks moisture out of the air. The wet POE doesn't lubricate well. The water in the POE corrodes AC parts.



If the system is at 0 psig. Pressurize it with Nitrogen, find and fix the leak. Replace the Receiver Dryer or Accumulator add back some "oil" and recharge.

You are correct Poly Ester oil's are not an oil, but a synthetic oil! A quality POE such as BVA Auto 100 will not attract any moisture when going from original container to the vehicle. If you sit it out in the open with the cap off it can collect moisture, more so if its raining! We are going on 10 years of use with either Texaco HFC 100 or the BVA Auto 100 POE and have yet to find a better oil for auto a/c systems.

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When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

Test Specimen on Tue September 20, 2005 4:20 PM User is offline

Quote
Originally posted by: PredatorOmnivore
On the other hand, some R-134a systems use POE "oil" . POE is not a true "oil" that is non-polar. POE is hygroscopic. It sucks moisture out of the air. The wet POE doesn't lubricate well. The water in the POE corrodes AC parts.



If the system is at 0 psig. Pressurize it with Nitrogen, find and fix the leak. Replace the Receiver Dryer or Accumulator add back some "oil" and recharge.


A case where too little knowledge about lubricants leads to bad conclusions. You are not doing anyone any favors by pushing people's buttons without knowing what you are talking about. I know you are only repeating what someone else told you, but it is bad information none the less.

Wet POE actually lubricates compressors better than dry POE, and is a better lubricant than any mineral based oil. It surprised me the first time I ran a test stand with wet POE, but after thinking it through it made sense. The moisture promotes the coating of the metal wear surfaces with a more slippery metal soap, and leads to lower friction coeficcients. There are other potential problems with wet POE like the possibility of wax-like deposits in the expansion device, but lubrication is not one of them.

There is little risk of corroding the A/C components from moisture, because the systems have almost no oxygen present. This is true with any lubricant. The more hydroscopic lubricants actually can lead to lower corrosion at the same moisture levels because the lubricant holds onto the dissolved moisture tighter, and the metal surface doesn't get to see as much of the moisture.

As Chick said, if hydroscopic lubricants were a problem, then PAG would be a disaster. Not so in real life.




Edited: Tue September 20, 2005 at 4:24 PM by Test Specimen

TRB on Tue September 20, 2005 4:56 PM User is offlineView users profile

There was a guy that used to say PAG would eat your whole vehicle apart in 3 years. Even if the system was never opened thus the shorter warranty offered by the manufactures . As with much of the "information" provided these days you need to use more then one or two sources. Heck the other day on another forum I read about how great sealers were for the poor and broke!Poster stated these products were great for someone trying to get their system working and anyone saying differently needed to use the products. Well how many times have we read posts about sealers causing huge system issues after being used? Well after reading those posts and real data on the products. I say the only one that benefited from the use of a sealer was the sales representatives bank account, which is fine. But might not hurt to inform readers that their is some dangers when using such a product. instead of making it sound like its a life saver without hazards!

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When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com


Edited: Tue September 20, 2005 at 10:09 PM by TRB

S10EV on Fri June 25, 2010 12:02 AM User is offline

Test Specimen,

I have a very rare ALL-Electric S10-EV that was produced in 1998 by General Motors. I'm having some A/C and Heat Pump problems with it, and I'd love to hear a little of your expertise on auto a/c before I finish up the work I'm doing. I'm very impressed with your deep knowledge. If you're still on this forum, can you send me an email to nielsen--at--spamcop--dot--net? I'd be extremely grateful.

Thanks,

Niel

newton5 on Sun June 27, 2010 2:50 AM User is offlineView users profile

Holy resurrected thread!

S10EV,
You may want to start a new thread about your (really cool,IMHO) truck.
Test Specimen is still around I believe, as are many new faces with lots of knowledge to share.

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