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Farf
Samba Member
Joined: July 12, 2009
Posts: 463
Location: Colorado
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 Posted: Fri Jul 30, 2021 5:56 pm Post subject: Re: Flushing PAG from new AC compressor to use mineral oil |
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| The mixing of a trace amount of PAG with mineral oil will not form a gel or sludge. It's more about the type of oil and its ability to mix with the refrigerant (miscibility). Since you are using RedTek you have no issues to concern yourself with. |
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djkeev
Samba Moderator
Joined: September 30, 2007
Posts: 32988
Location: Reading Pennsylvania
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djkeev
Samba Moderator
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Location: Reading Pennsylvania
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syncro surf
Samba Member
Joined: June 06, 2017
Posts: 189
Location: Maine
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| Posted: Fri Jul 30, 2021 3:28 pm Post subject: Re: Flushing PAG from new AC compressor to use mineral oil |
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Thanks everyone for the very helpful perspectives. The only problem I see with looking at Sanden's advice is that they are talking about small amounts of mineral oil in PAG. It does not necessarily follow that small amounts of PAG in mineral oil will behave the same.
From all my reading about oil from various sites (which involves a lot of reading between the lines) I feel like I probably could "send it" with what I've done and be fine. But it seems like everyone here who has done this has flushed with a solvent. Nobody has spoken up who has actually flushed with just mineral oil successfully. As everything in my system, with the exception of the evaporator is new, I'm not sure I want to be the guinea pig.
Harry Callahan's looking at me "You gotta ask yourself one question - do you feel lucky? Well do you punk?" |
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djkeev
Samba Moderator
Joined: September 30, 2007
Posts: 32988
Location: Reading Pennsylvania
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skills@eurocarsplus
Samba Peckerhead
Joined: January 01, 2007
Posts: 17836
Location: sticksville, ct.
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| Posted: Fri Jul 30, 2021 7:57 am Post subject: Re: Flushing PAG from new AC compressor to use mineral oil |
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| djkeev wrote: |
And more........
Sanden does not seem concerned about minimal mineral oil being in the compressor when switching to PAG ....... if they are not concerned, you need not worry either.
I'd be trusting Sanden over local wrench turners opinions.
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sanden also sells compressors, and denies warranty claims.
whatever....he asked for opinions and i gave mine after being a tech for 30+ years now.
if you brought it to me....i spelled out exactly how i would do it. you never know who has done what to these old systems at this stage in the game.
dunno...guess spending more than 1/3 of my life in dealerships i have had "cover you ass" pounded into my head.
some have the "send it" mentality....that line of thought has never worked favorably for me
_________________
| gprudenciop wrote: |
my reason for switching to subaru is my german car was turning chinese so i said fuck it and went japanese....... |
| Jake Raby wrote: |
| Thanks for the correction. I used to be a nice guy, then I ruined it by exposing myself to the public. |
| Brian wrote: |
| Also the fact that people are agreeing with Skills, it's a turn of events for samba history |
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djkeev
Samba Moderator
Joined: September 30, 2007
Posts: 32988
Location: Reading Pennsylvania
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djkeev
Samba Moderator
Joined: September 30, 2007
Posts: 32988
Location: Reading Pennsylvania
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djkeev
Samba Moderator
Joined: September 30, 2007
Posts: 32988
Location: Reading Pennsylvania
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skills@eurocarsplus
Samba Peckerhead
Joined: January 01, 2007
Posts: 17836
Location: sticksville, ct.
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| Posted: Thu Jul 29, 2021 7:12 pm Post subject: Re: Flushing PAG from new AC compressor to use mineral oil |
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| syncro surf wrote: |
Skills - do you know of an appropriate solvent?
Thanks |
this
https://www.napaonline.com/en/p/TEM419955?cid=paid...aw.ds&
or DURA flush solvent.
problem with brake cleaners is it doesn't flash off quick and you can go out the next day and pour it out.
DURA (now DURA 2) would about boil at room temp. the shit was evil but worked real good.
that is what we used doing retrofits at the dealer and if a customer wouldn't spring for a whole new system if the compressor blew chunks into the system we'd flush it with that stuff
brake clean can work, no doubt but be VERY careful you don't have ANY trace of it in the components. even a small amount will strip the lubricity out of the oil and/or mix and make poo
_________________
| gprudenciop wrote: |
my reason for switching to subaru is my german car was turning chinese so i said fuck it and went japanese....... |
| Jake Raby wrote: |
| Thanks for the correction. I used to be a nice guy, then I ruined it by exposing myself to the public. |
| Brian wrote: |
| Also the fact that people are agreeing with Skills, it's a turn of events for samba history |
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Zeitgeist 13
Samba Member
Joined: March 05, 2009
Posts: 12167
Location: Port Manteau
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| Posted: Thu Jul 29, 2021 6:47 pm Post subject: Re: Flushing PAG from new AC compressor to use mineral oil |
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Rubbing alcohol also evaporates quite quickly, especially when exposed to compressed air rushing by. Any solvent that lifts the oil and doesn't leave a residue or affect the seals should work. It ain't brain rocketry.
_________________
Casey--
'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik? |
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pdm777
Samba Member
Joined: August 06, 2012
Posts: 348
Location: Clovis, CA
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| Posted: Thu Jul 29, 2021 6:39 pm Post subject: Re: Flushing PAG from new AC compressor to use mineral oil |
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rubbing alcohol contains water.
Methanol does not.
Methanol is fine to flush lines and compressors.
Make sure you drain ALL of it out,
then run compressed air to evaporate any traces.
Don't overthink it.
A couple hours of methanol exposure will not
dissolve your seals or compromise aluminum.
You'll be surprised how much 'snot' comes out of
the compressor and the lines, old yellow flourescent dye, etc.
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1990 Westy Full Camper |
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Zeitgeist 13
Samba Member
Joined: March 05, 2009
Posts: 12167
Location: Port Manteau
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| Posted: Thu Jul 29, 2021 4:14 pm Post subject: Re: Flushing PAG from new AC compressor to use mineral oil |
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Yes, I flushed the new AC compressor for my TDI Vanagon with rubbing alcohol. I didn't invent this process. It's been used for decades.
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Casey--
'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik? |
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syncro surf
Samba Member
Joined: June 06, 2017
Posts: 189
Location: Maine
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| Posted: Thu Jul 29, 2021 3:59 pm Post subject: Re: Flushing PAG from new AC compressor to use mineral oil |
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| djkeev wrote: |
| Don't overthink this. |
Ha - Impossible.  |
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djkeev
Samba Moderator
Joined: September 30, 2007
Posts: 32988
Location: Reading Pennsylvania
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syncro surf
Samba Member
Joined: June 06, 2017
Posts: 189
Location: Maine
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| Posted: Thu Jul 29, 2021 3:29 pm Post subject: Re: Flushing PAG from new AC compressor to use mineral oil |
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| Is the Methanol ok for the seals and is it just aluminum corrosion that is the concern? |
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syncro surf
Samba Member
Joined: June 06, 2017
Posts: 189
Location: Maine
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| Posted: Thu Jul 29, 2021 3:23 pm Post subject: Re: Flushing PAG from new AC compressor to use mineral oil |
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| Dave - I'm kind of with you on the just run it, there cannot be much PAG left in there. I'm just trying to dig up as much actual experience as I can before pulling the trigger. I like that Casey has successfully used alcohol. As of now that's my back up plan if I chicken out on the just run it plan. |
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Howesight
Samba Member
Joined: July 02, 2008
Posts: 3404
Location: Vancouver, B.C.
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| Posted: Thu Jul 29, 2021 3:08 pm Post subject: Re: Flushing PAG from new AC compressor to use mineral oil |
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Terry Kay recommended air brake antifreeze. I have used it to flush AC lines. It works. Most FLAPS will sell it. The question, as DJKeev has identified above, is whether it will be needed.
There are so many crevices in the compressor where PAG oil could hide that I do think flushing with such a fluid is a good idea to get the PAG out. The air brake anti-freeze typically is mostly methanol. It will remove most of the old oil and if you hit the compressor with compressed air, it will mostly evaporate. The remainder of evaporation (if any) of this liquid will occur when you vacuum the system.
The key thing, if you go this route, is to get the compressed air into the compressor ASAP, repeat the fluid flush again if you choose, compressed air again, and then add your final oil, drain, and add again.
The air brake line antifreeze typically is 60 to 100% methanol. Methanol corrodes aluminum, which is what the pistons and compressor case are made of. This is why you need to blow compressed air through the compressor and then fill with your final oil ASAP if you use air brake antifreeze. Do any such flush outdoors. Wear gloves and a respirator. Methanol is not to be trifled with. If it lights up, you won't see the flame. Keep a garden hose or fire extinguisher close by.
I would never mix these two kinds of oil, PAG and mineral. For what it is worth, PAG is actually a great lubricant and works well with RedTek or R134A.
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kourt
Samba Member
Joined: August 13, 2013
Posts: 2316
Location: Austin, TX
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| Posted: Thu Jul 29, 2021 3:01 pm Post subject: Re: Flushing PAG from new AC compressor to use mineral oil |
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The old Terry Kay method, which I have used before, is to use truck air brake antifreeze solution to clean out your AC lines. It does work well for this purpose. I have run it through all components except the compressor.
It works like this: you pour the solution in to a container that can be pressurized. Put the cap on the container and pressurize it with an air compressor. Open your AC system and make sure the solution has a place to go--usually placing an open hose in a bucket. Place the nozzle of the pressurized, loaded container on the open hose and open the nozzle jet. The solution will blast out of the container and through the hose and into your bucket. Use additional compressed air directly in the AC hose to blast out any remaining solution.
There are specialty products from Intermatics that do the same thing. I find that the air brake antifreeze is more available over the counter at my local auto parts store (O'Reilly).
kourt |
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syncro surf
Samba Member
Joined: June 06, 2017
Posts: 189
Location: Maine
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| Posted: Thu Jul 29, 2021 3:01 pm Post subject: Re: Flushing PAG from new AC compressor to use mineral oil |
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Thanks - I have read TK's threads and did use air brake cleaner to flush my evaporator.
Most flushing discussions are about flushing/cleaning the system excluding the compressor.
I guess what I really need to know is what turns what to goo. When going from mineral to PAG, which is what all the discussions are about, it seems to be accepted that you can have up to 5% residual mineral oil in your PAG and not have a gelling problem. So in that case the flushing method that I used would be ok.
The reverse could be a different story if it is the mineral oil that turns the PAG to goo. If I have any residual PAG there will certainly be much more than 5% ratio of mineral oil present. Does that mean that even a trace amount of PAG will eventually turn to something that will clog my system?
My big mistake was not deciding to replace the compressor in the first place. I could have just coverted to PAG when I assembled everything - but that ship has sailed. |
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