If you buy a new compressor, it should come with instructions on what type to use. New compressors usually take PAG46, but always check so you don't void the warranty.
Generally,
PAG46 - new compressors with R-134A PAG150 - old compressor with R-134A 525 Mineral oil - R-12
What is the best oil to use for the 134a system, and how much is needed for a new install?
If the system was previously converted to R-134a there should be a sticker (required by law) stating the refrigerant and lubricant used. The two basic choices for R-134a are PAG or ester oil, and you do not want to mix the two in the same system. If there is no sticker, you may be able to drain some lubricant out of the old accumulator and have a professional identify it for you.
If this is a new R-134a conversion, GM states that only PAG should be used. The correct volume of lubricant is the same as originally specified for the Fiero by GM. The GM/Helm Factory Service Manual will have that information.
Definitely call 4 Seasons customer service and find out the lubricant type and viscosity they recommend. The life of your new compressor and your warranty both depend on it.
[This message has been edited by Marvin McInnis (edited 07-28-2013).]
The 'Compressor Installation Procedures' that came with the compressor say the following:
"To ensure proper compressor lubrication, install half the required system oil in the suction side." "The remaining amount of required system oil should be installed in the accumulator or low side of the system."
Is that really a good idea, putting oil directly in the accumulator? (I am installing a new accumulator)
What is another location, on the low side of the system, that the oil can be added?
Thanks for the help.
[This message has been edited by hdryder (edited 07-28-2013).]
Is that really a good idea, putting oil directly in the accumulator?
Yes. During normal operation the accumulator, among other things, acts as a reservoir for both refrigerant and lubricant. The accumulator even includes a metering orifice to control the flow of lubricant to the compressor.
From a 4 Seasons tech note titled PAG Confusion: The four viscosities [of PAG] we offer are 46, 100, 125, and 150 centistoke ... The 150 centistoke lubricant is used primarily on the Delphi-Harrison compressors (General Motors) ... The 125 is a special lubricant for the OEM Delphi-Harrison V5.
[This message has been edited by Marvin McInnis (edited 07-28-2013).]
Do you know what kind of A/C oil GM used in 1987 for the R12 system?
I have read GM now recommends PAG oil, but I am not sure if that was a changed with the R134a systems.
For R-12 systems use only mineral oil, nothing else. Never use PAG or ester oil with R-12.
For R-134a systems use PAG or ester oil, never mineral oil. Don't mix PAG and ester oil in the same system.
The above notwithstanding, always use mineral oil (not PAG or ester oil) to lubricate the O-rings when installing them on AC fittings, regardless of the refrigerant type being used.
Mineral oil is insoluble in R-134a. According to both GM and the EPA, any residual mineral oil in an R-12 system converted to R-134a will migrate harmlessly to the low points in the system and remain there.
[This message has been edited by Marvin McInnis (edited 07-28-2013).]
PAG oil is the best oil to use in a completely new system but it is also highly incompatible with the old R-12 mineral oil. When you start with an R-12 system it is bound to contain a residue of 525 mineral oil. You can only blow out so much but some will always remain and if you flush with solvent you risk hose leakage. When doing an R-134a conversion, I only use Ester oil. I currently run two R-134a converted A/C systems that run Ester Oil. Both have been working for 3 and 5 years without a single problem. Remember PAG and mineral oil do not mix.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Powerlog manifold, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
... if you flush with solvent you risk hose leakage.
I disagree:
1) Both GM and the EPA state that mineral oil will permanently seal old-style rubber hoses. They may leak from age and repeated flexing, but not because the mineral oil has been leached out of them. That said, if you car still has 20+ year old rubber refrigerant hoses I would recommend replacing them on general principles.
2) Every Fiero I've seen is already equipped with barrier-type hoses, which do not depend on oil to make them impervious to R-134a.
quote
Remember PAG and mineral oil do not mix.
So what? Mineral oil is incompatible with R-134a, too. Both GM and the EPA state that any residual mineral oil in a system converted to R-134a will migrate harmlessly to the low points of the system and remain there.
[This message has been edited by Marvin McInnis (edited 07-29-2013).]
Mineral oil is incompatible with R-134a, too. Both GM and the EPA state that any residual mineral oil in a system converted to R-134a will migrate harmlessly to the low points of the system and remain there.
The reason that we do not use PAG oil in R-134a conversions is because it is incompatible with 525 mineral oil. Left over mineral oil will not circulate in an R-134A system that contains PAG oil and it may gel because of it. Ester oil is specially formulated to mix with residual mineral oil. Residual mineral oil combines and will circulate with Ester Oil in a system that uses R-134a That's why Ester Oil is the recommended choice for R-134a conversions or retrofits and why 100% of the R-134a conversion kits come with it.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Powerlog manifold, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
From GM TSB #33-12-26: Retrofitting R-12 Vehicles to R-134a - May 10, 1997
"RESIDUAL MINERAL OIL
"THE CONCERN THAT MINERAL OIL IS CHEMICALLY INCOMPATIBLE WITH R-134A AND/OR PAG LUBRICANT HAS BEEN PROVEN TO BE UNTRUE. A NORMAL CHARGE OF MINERAL OIL LEFT IN THE A/C SYSTEM AFTER A RETROFIT TO R-134A WILL NOT DAMAGE THE SYSTEM. MINERAL OIL, HOWEVER, DOES NOT MIX WELL WITH R- 134A, AND WILL NOT PROVIDE ADEQUATE LUBRICATION. TESTS ON BOTH THE ORIFICE TUBE AND TXV SYSTEMS SHOW THAT THE MINERAL OIL PARKS IN PLACES SUCH AS THE ACCUMULATOR, AND DOES NOT APPRECIABLY AFFECT PERFORMANCE OR DAMAGE THE SYSTEM."
From GM TSB #33-12-26: Retrofitting R-12 Vehicles to R-134a - May 10, 1997
"RESIDUAL MINERAL OIL
"THE CONCERN THAT MINERAL OIL IS CHEMICALLY INCOMPATIBLE WITH R-134A AND/OR PAG LUBRICANT HAS BEEN PROVEN TO BE UNTRUE. A NORMAL CHARGE OF MINERAL OIL LEFT IN THE A/C SYSTEM AFTER A RETROFIT TO R-134A WILL NOT DAMAGE THE SYSTEM. MINERAL OIL, HOWEVER, DOES NOT MIX WELL WITH R- 134A, AND WILL NOT PROVIDE ADEQUATE LUBRICATION. TESTS ON BOTH THE ORIFICE TUBE AND TXV SYSTEMS SHOW THAT THE MINERAL OIL PARKS IN PLACES SUCH AS THE ACCUMULATOR, AND DOES NOT APPRECIABLY AFFECT PERFORMANCE OR DAMAGE THE SYSTEM."
(Caps in the original)
If you really think that mineral oil mixes well then put PAG oil in your system- just have a few hundred ready for a new compressor.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Powerlog manifold, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
If you really think that mineral oil mixes well then put PAG oil in your system- just have a few hundred ready for a new compressor.
1) I have never said that "mineral oil mixes well with PAG," nor do I believe so. I cited several sources that indicate just the opposite.
2) PAG is GM's recommeded lubricant for R-134a systems, not mine. It is GM's and the EPA's position that residual mineral oil is harmless in an R-12 system converted to R-134a.
3) Why would anyone want to put PAG in an R-12 system?
If you want to argue further, you'll have to find someone else. If I offended you by presenting information that contradicted you, that was not my intent. It's really not about you and me. My only interest is that full and correct information is presented here. I never said not to use ester oil, rather that GM recommends only PAG. I never said that mineral oil and PAG were compatible, but merely quoted GM and the EPA that there would be no harm having both present in an R-134a system.
The GM information I cited is more than ten years old now. If you have newer or more authoritative information, I would be happy to review it.
[This message has been edited by Marvin McInnis (edited 07-30-2013).]
