Which PAG oil?

[jtrux]

I'm converting over to r134a and wanted to know what PAG oil to get?

1991 V1500

San Antonio, TX

New AC Delco R4 compressor

46, 100, 150, etc?

 

[Wes Harden]

Mostly use 100

 

[jtrux]

Where do you find out which to use?

 

[Wes Harden]

Universal Air Conditioning System PAG Oil (15-118) by ACDelco. Volume: 16 oz. ACDelco Refrigerant Compressor Oil (150 Viscosity) is intended for use on R4 and A6 compressors within R-134a refrigerant systems. This product must be used for GM-Harrison manufactured compressors using R-134a refrigerant oil.
Brand: ACDelco

Seems GM wants 150. But everything in our fleet gets 100, since all the shops only have one recovery machine, and the vehicle can be serviced at any shop at any time, we all use the same oil

 

[jtrux]

Universal Air Conditioning System PAG Oil (15-118) by ACDelco. Volume: 16 oz. ACDelco Refrigerant Compressor Oil (150 Viscosity) is intended for use on R4 and A6 compressors within R-134a refrigerant systems. This product must be used for GM-Harrison manufactured compressors using R-134a refrigerant oil.
Brand: ACDelco

Seems GM wants 150. But everything in our fleet gets 100, since all the shops only have one recovery machine, and the vehicle can be serviced at any shop at any time, we all use the same oil

Thanks a lot, man.

 

[Blue85]

Everything I've read suggests the 150 viscosity for R-4 compressors. I don't mind buying 150 for my square and 50 for my IFS trucks because my early 90's R-4 is still running quiet with it.

 

[MaxPF]

I'm converting over to r134a and wanted to know what PAG oil to get?

1991 V1500

San Antonio, TX

New AC Delco R4 compressor

46, 100, 150, etc?

Back in the day, when R-12 was the gas used in the AC system of your truck, the mineral oil used in the R4 was 500 SUS (or 525 SUS), which equates to ISO 100. When R-134a came along and PAG oil was used, GM bumped the viscosity up to ISO 150. The R4 is very critical of it's lubrication because it has no oil sump (all the oil circulates in the refrigerant) and the Scotch yoke drive mechanism is fairly high friction. I wouldn't have any problems using ISO 100, or even ISO 68 or 46, in an A6 (which is a swash-plate compressor similar to a modern Denso, Seltec, FS-10, etc), but I would definitely stick with the GM-specified ISO 150 lube for the R4. ISO 100 likely won't give as long life in that application.

FWIW, it is VERY simple to convert from an R4 to an ear-type Sanden SD7H15 or Seltec TM-16HS (or TM-16HD) compressor. You would need to redo the suction and discharge hoses and cut the bullet connector off the Sanden or Seltec clutch lead and crimp on a male blade to plug into the R4 compressor connector (you want to retain the diode that is on the connector). Depending on where you shop the cost probably isn't much more than an R4, and as long as the system is completely clean the Sanden or Seltec compressor will darn near last forever.

 

[Blue85]

FWIW, it is VERY simple to convert from an R4 to an ear-type Sanden SD7H15 or Seltec TM-16HS (or TM-16HD) compressor.

Having custom hoses made, hacking the factory wiring and running spacers on the compressor mounting bolts is doable but not "VERY simple". I think you're also assuming he will swap out his condensor for a parallel flow to help make up for the smaller displacement of the Sanden (they're also smaller so the quantitative effectiveness of that is still TBD). So now he's spent an additional $500 and replaced 1/2 of the A/C system compared to he appears to be planning.

 

[jtrux]

For the time being I will stick with the R4 that I bought. I am planning on a 6.0 swap in the future after I go through the engine I have and source a 4L80E.

Thanks for all the info.