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Best way to flush POE Pages: 12

terryk on Thu June 30, 2005 12:00 AM User is offline

Year: 91
Make: Chevrolet
Model: K1500
Engine Size: 305
Refrigerant Type: R134a
Country of Origin: United States

What works best to flush out POE? I want to switch to PAG.

Terry

k5guy on Thu June 30, 2005 12:04 AM User is offline

I wouldn't do that.... POE is better with R134a. Why do you want to switch?

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MrBillPro on Thu June 30, 2005 12:06 AM User is offlineView users profile

Quote
Originally posted by: k5guy
I wouldn't do that.... POE is better with R134a. Why do you want to switch?

And might I add a lot more forgiving if there is any moisture in the system.


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Don't take life seriously... Its not permanent.

zuperdee on Thu June 30, 2005 1:08 AM User is offline

This is something I'm now curious about: exactly how is POE better than PAG? As I understand it, it may be less hygroscopic than normal PAG, but double-end capped PAG is also supposedly less hygroscopic than normal PAG, and POE is supposedly not as good in terms of lubricity as PAG, which is why the vast majority of OEMs use PAG.

k5guy on Thu June 30, 2005 1:38 AM User is offline

Dupont states in their technical literature on Suva (R134a). Suva Report

"PAGs with low viscosity show good solubility, but as viscocity increases, they become less soluble. Polyol ester lubricants, of which there are many types, generally show good solubility with HFC-134a. When compared to PAGs, ester lubricants are more compatible with hermetic motor components and are less sensitive to mineral oil and CFC-12 remaining in the refrigeration system."

This document was written in 2004, and double-ended PAG was available at that time.

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terryk on Sat July 02, 2005 4:11 PM User is offline

The reason I want to switch is:

1. GM told me to use PAG with my new R4 and I didn't. I used POE.
2. The brand spanking new GM R4 compressor rattles.
3. I raised the charge to 110% of the R12 charge hoping it was an undercharge condition and the rattling didn't improve. I didn't drive it around during this test but watched everything closely with the gauge. If it was any quieter I couldn't tell.

There is plenty of oil in the system (about 8oz). The rattle is loud enough you can hear it with the hood closed. If the PAG doesn't quiet it down, I will run it until it dies and retrofit a different compressor.

Bigchris on Sat July 02, 2005 4:27 PM User is offline

R4s rattle. That's what they do.
Before changing oils I'd recommend that you double check all mounting bolts for tightness and doublecheck belt tension. One of these may bring the rattle to a tolerable level although it is not uncommon for some rattle to persist at idle.

TRB on Sat July 02, 2005 5:12 PM User is offlineView users profile

If you used the correct amount and a quality POE, its not the oil creating the rattle!

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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: Sat July 02, 2005 at 5:12 PM by TRB

k5guy on Sun July 03, 2005 1:55 AM User is offline

My R4 has a little roar, but I can't hear it from inside the truck. I have to have the hood open to hear it. I used POE on it, and it worked fine until the evap leaked. But thats another story.


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Bigchris on Sun July 03, 2005 2:26 AM User is offline

Mine is in a '90 Caprice and it was a brand new GM replacement part six years ago. It has always been noisy and is very sensitive to idle speed. You can hardly notice it from inside the car but if you step outside it sounds like someone is shaking a coffee can full of nuts and bolts under the hood - at 650 rpm idle. Bring the idle speed up to 750 or 800 rpm and the noise disappears. It continues to cool like a champ so terryk may be in for a long wait before his expires.

Edited: Sun July 03, 2005 at 2:27 AM by Bigchris

terryk on Sun July 03, 2005 10:13 PM User is offline

Well, there is not much more I can try. When everything is the way everyone says it should be.....then.....?

This rattle is more of a clatter. It's there anytime it turns. You can hear it in the cab of the truck.

It's not loose bolts or belts or anything to do with turning it or the mounting. The original was quiet other than a slight poofing sound.

Beats me what to do now.

TRB on Sun July 03, 2005 10:24 PM User is offlineView users profile

What brand of compressor is it? How much oil did you add too the system?

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

terryk on Sun July 03, 2005 10:30 PM User is offline

GM factory compressor. New.

7.5oz total BVA. 5oz in the compressor and spun it a million times (cramp, cramp). 2.5oz in the accumulator.

terryk on Sun July 03, 2005 10:41 PM User is offline

ps. Don't get me wrong. It works like a dream. It was my first "done right" conversion (no death kit) thanks to this forum! I've followed the same suggestions here on my other three cars (DA6's) and couldn't be happier. Now this dang R4......

k5guy on Sun July 03, 2005 11:48 PM User is offline

Lots of people complain about R4s. But once you see how many cars and trucks use them, you know they are built tough. Just take care of them, and they last a long time.

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terryk on Sun July 03, 2005 11:50 PM User is offline

Are they loud enough for people to think you are running a diesel?

bohica2xo on Mon July 04, 2005 3:29 AM User is offline

Ok, everyone here that knows me is aware I am not a fan of the R4, or PAG lubricants - so hold on to your coffee cups.

Terry, I will answer your question on how to swap oils - but let me explain why.

The GM specification for oil in the R4 is 150 ISO viscosity. The BVA oil is 100 ISO viscosity. There are additional differences in the lubricants as well. PAG tends to be 'tacky', it holds on to surfaces well.

PAG is used in industrial cutting fluids, for yet another of it's properties - it drops out of solution at high temperatures. What this means to a cutting tool, is the oil stays behind when the coolant is boiling off of the tool. According to the tribologists, PAG does the same thing in a compressor - it is not easily carried off by refrigerants at high temperatures.

While BVA certainly has enough load carrying capacity to be a great lubricant, it may well be that the added viscosity and tack of PAG 150 provides enough "cushion" to reduce the noise in an R4. The possibility of a higher oil concentration may also contribute.

PAG's do polymerize water, but I believe the OEM's use them because of that - not in spite of it. The system only needs to last as long as the warranty, and a 50-50 mix of PAG and water still looks like oil, and pours at about 25f - the system will still run. POE, on the other hand will reject water, and at some point the ice crystals in the system may become a problem....


To convert to PAG:

You will need to flush your system completely. Then you need to flush your compressor. There is a compressor flushing thread in the FAQ's. You will need to replace your accumulator.

Since you have a fresh system flushing will not be too bad - just need to get all of the POE out.


If you do convert, please keep us posted on the results, and be sure you use 150 ISO PAG....



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"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

zuperdee on Mon July 04, 2005 4:11 AM User is offline

This is very interesting... I also have an R4 compressor, but I used the Supercool PAG Blue that is sold here. The viscosity of this is supposedly 125, which is GM approved. I've also heard that the official AC Delco oil is 125. Am I running the risk of compressor oblivion with my 125 viscosity?

zuperdee on Mon July 04, 2005 4:14 AM User is offline

Oh, and for the record, since the original concern in this thread was noise: my R4 seems to run very quietly with the Supercool PAG Blue oil, and my R4 is REBUILT by AC Delco. I've NEVER had a complaint about noise with this compressor. In fact, it actually seems to run quieter than my old R4 did with R12 and mineral oil. Again though, MY question of the day: am I running a risk by using 125 instead of 150?

bohica2xo on Mon July 04, 2005 4:20 AM User is offline

Zuperdee:

The 100 and 125 viscosity lubes seem to have plenty of load carrying capacity - I would not worry about your R4 Many miles have been covered by compressors full of 100 ISO oils.

The only issue here is excessive noise. Some R4's are worse about it than others. I suspect the manufacturing tolerance is generous on the R4, and some may pump fine while loud by comparison to others. Adding a reman into the mix, and a blend of parts across several years of manufacture re-assembled into a "fresh" compressor....

Your re-man was obviously the "right parts in the right case" - you have nothing to worry about.
.

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"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

Edited: Mon July 04, 2005 at 4:22 AM by bohica2xo

Gary Harrison on Mon July 04, 2005 9:27 AM User is offline

Regarding the R4 rattling, I had a 95 Suburban w/ R4 that apparently rattled badly at idle. Noise was difficult to isolate, but seemed to be the compressor. That is until I decided to check the bearing in the tensioner idler. I then noticed that accessory belt slack was allowing the tensioner arm to vibrate against the mounting bracket at idle. W/ increased engine speed the vibration stopped. A new belt fixed the problem.

good luck



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terryk on Wed July 06, 2005 12:59 AM User is offline

I have all new tensioners and idlers. It's clearly the compressor making the noise.

I'll swap the oil and see how it sounds. Thanks for all of the input folks! I've learned more on this site than any other!

TRB on Wed July 06, 2005 9:56 AM User is offlineView users profile

My 2 cents, its not the oil! We use the BVA Auto 100 all the time in R4 compressors. Does not matter if they are new or remanufactures and never have had a noise issue related to the lubricant. If you feel changing the oil will do the trick by all means go ahead and let us know of the results.

-------------------------

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

bohica2xo on Wed July 06, 2005 12:54 PM User is offline

Terry:

Please keep us up to date on the outcome of this experiment.


Tim:

I am not positive that the answer is oil viscosity either. This is not really about PAG so much as it is viscosity. The only 134a compatible 150 ISO lube available seems to be PAG. The manufactureres have been using PAG's for over a decade now, and generally they work for several years - as long as this poster is aware of the shortcomings and is willing to experiment, I see no problem.

While one case does not make a study, we can learn something here either way. I occasionally hear an R4 that sounds like a diesel at idle - the owners seem to be divided into two camps, "Replace that damn thing!" or "I don't care, it still blows cold". This particular time, we have someone willing to experiment.

It is in the best interests of any manufacturer to use the widest tolerances possible to reduce manufacturing costs. I think the R4 was designed for low cost mass production, and was put into production long before Six-Sigma quality was common to top tier automotive manufacturers. It was a cheaper alternative to the A6, and if a dealer had to replace 1% of them for noise complaints, they were still ahead of the game.


.

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"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

terryk on Wed July 16, 2008 1:39 PM User is offline

Three years later. Sounds like a diesel and cools like an iceberg. Still has the POE in it. I never swapped the oil.

Edited: Wed July 16, 2008 at 1:40 PM by terryk

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