OK, when to the Auto Zone to purchase two items for my 86 -- A/C.
(1) The material which I was reading indicated to use 525 viscosity Mineral Oil. -- they did not care that. Anyone know where they do? From the articles I read I should wipe the "O" rings down with them before installation.
(2) PAG oil -- again the articles state PAG 46 -- all I found was PAG 100 or 150. Can anyone tell me the different? and if a substitute is OK.
Sorry, gang it's my first time doing this and I am struggling.

Your knowledge on these subjects are needed and wanted, thanks...

From 4 Seasons:

"The four viscosities we offer are 46, 100, 125, and 150 centistoke. The smaller the number, the easier the lubricant tends to pour. A 46 centistoke is lighter than a 100 centistoke. Many times, the 46 grade is referred to as the ‘light weight’, the 100 as the ‘middle weight’, and the 150 as the ‘heavy weight’. The 125 is a special lubricant for the OEM Delphi-Harrison V5. General Motors determined that when the OEM V5 compressor is retrofitted, the system requires a specially formulated PAG lubricant.

"The 46 centistoke lubricant is used on many Nippon-Denso style compressors. This includes many of the Ford and Chrysler compressors. The 150 centistoke lubricant is used primarily on the Delphi-Harrison compressors (General Motors). The 100 centistoke lubricant is used on several import and aftermarket compressors."


On the other hand, here is what ACDelco Technical Service Bulletin 05D-J-114 (2005) has to say:

"PAG lubricant – ... 600 SAE or 150 ISO viscosity for all R4 and A6 compressors. For all other ACDelco supplied service replacement compressors, use the 46 ISO viscosity universal PAG oil ...."

(It is not clear to me whether "A6 compressors" includes the DA6/HR6 compressors used in Fieros.)


However, another Tech Note from 4 Seasons states this:

"This is to notify field technicians that there is a change in the type of lubricating oil that is applied to certain General Motors Corporation vehicles. Since 1994, technicians have been able to depend upon almost all GM vehicles having Delphi-Harrison compressors and HFC134a to use the 150 viscosity PAG oil.

Beginning with the 2000 year model, Cadillac introduced a Mitsubishi compressor (type MCS-130-C) on the Deville and Seville platforms. This compressor uses the 100 viscosity PAG oil.

Also, in the 2000 year model, Chevrolet/GMC started using Denso compressors (types 10S20F and 10S17F) on the Silverado/Sierra, Tahoe/Yukon and Suburban platforms. General Motors originally wanted the 150 viscosity PAG oil, but has recently announced that they went with the 46 viscosity PAG oil. This follows the Denso guidelines for other Denso manufactured compressors."

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My personal conclusion is that 150 viscosity PAG should be used in R-134a systems for the GM/Harrison (ACDelco) HR6 compressors in our Fieros. The earlier (and troublesome) DA6 compressors should not be used in systems converted to R-134a. 125 ISO viscosity PAG is probably the best choice in R-134a systems for the GM/Harrison V5 compressors used in some 4-cylinder Fieros.

Two questions:

1) What refrigerant are you using? Use mineral oil for R-12 systems, and PAG for R-134a.

2) What viscosity does the manufacturer of your compressor recommend? If known, that is the correct viscosity to use. A new or remanufactured compressor should have a tag attached that specifies the correct lubricant viscosity to use.

Any viscosity of refrigerant-grade mineral oil can be used on the rubber O-rings. Always use mineral oil on the O-rings, not PAG.

[This message has been edited by Marvin McInnis (edited 04-27-2013).]

^ EXACTLY what he said. As for where to get it, I've seen 525 mineral oil at a coue small independent parts stores, and NAPA can order it if you give them the part number. I think I've posted it on here before, it's hard to search from my phone...

PAG 150 is available at most Advance and Auto Zones during the summer.

Easiest place to get either is to just order it online.

When i got my rebuilt compressor it already had some oil in it and the instructions recommended using the same.

I always use ester oil on 134a conversions, it is compatible with both oils.
PAG and mineral do NOT mix.
Pag is for when you replace EVERYTHING with brand new parts, and don't have any mineral oil in any part of the system.
BTW the correct thing to use on o-rings is nylog, usally found from A/C supply shops, Autozone I don't think carries it and prob wouldn't know what you are talking about.

But to answer the question
mineral oil is for R12 only
PAG is for 134a only
and then
ester oil is for conversions r12 to 134a

------------------
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quote Originally posted by sardonyx247: I always use ester oil on 134a conversions, it is compatible with both oils. PAG and mineral do NOT mix.

ACDelco Technical Service Bulletin 05D-J-114 (2005) states the GM position that only PAG should be used in all R-134a systems, OEM or conversion, and that Ester oil should not be used.

Mineral oil is not soluble in R-134a, and it is correct that PAG and mineral oil do not mix. But both GM and the EPA state that any residual mineral oil in an R-12 system converted to R-134a will migrate harmlessly to the lowest points in the system and remain there. It's desirable to drain as much old mineral oil as possible when converting from R-12 to R-134a, but neither GM nor the EPA recommend flushing the old system unless there is debris present (e.g. following a compressor failure).

quote Pag is for when you replace EVERYTHING with brand new parts, and don't have any mineral oil in any part of the system. ... mineral oil is for R12 only PAG is for 134a only and then ester oil is for conversions r12 to 134a

There is no question that mineral oil is only used with R-12, and that neither PAG nor Ester oil are ever used with R-12. Two key factors concerning R-134a systems, OEM or conversion:

1) Always use the lubricant type and viscosity specified by the compressor manufacturer.

2) Never mix PAG and Ester oil in the same system. If replacing the compressor, be sure the new one is approved for use with the lubricant type already in the system. EPA regulations require that a tag or label be attached near the service ports indicating both the refrigerant and lubricant used in a converted system. Unfortunately, this label is often missing from shade tree conversions.

The above notwithstanding, many people have used Ester oil successfully in R-12 to R-134a conversions. Just be sure that the compressor manufacturer approves its use. YMMV.

[This message has been edited by Marvin McInnis (edited 04-28-2013).]

FWIW, I ran ester oil in my 96 Camaro with the V5 compressor for a couple years with no problems, and I also ran ester in my Fiero with a rebuilt HR6 with no issues for about 2 years.

I think ester is more "forgiving" because its a middle-weight iso 100 grade that works with a wide variety of systems, but it's not really optimal for most of them (mostly for compressor wear). It'd be like running 20w-50 oil in an engine designed for 5w-30, or vise versa - the engine would still run for a while but the lubrication would not be ideal. If you have the system opened up its no more trouble just using the correct PAG oil.

[This message has been edited by masospaghetti (edited 04-30-2013).]

Neither PAG nor Ester oil are particularly good lubricants, and both of them are hygroscopic (i.e. they readily absorb and retain moisture), but they're the only choices we currently have for use with R-134a.

[This message has been edited by Marvin McInnis (edited 04-30-2013).]

Sorry to break in to this thread but I'm in the process of putting a new A/C system on my '85. I have a new compressor which I'm going to install then take the car to a shop to finish. I have the 134a conversion kit. When installing the compressor, how much "ester oil" should I put in and in which hole, the smaller hose side, or the bigger hose side? Then I'm going to hook the lines up and take it to be charged.