A/C PAG oil amount - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**Wgesnerjr** · 05-07-2019, 01:26 PM

Hi there,
I am not near my service manuals but would appreciate some quick help. How much total PAG oil does the A/C system take in a 1985 C10? The system has been fully evacuated and cleaned. New condenser core, Orifice tube, Receiver/Drier, Saden type Compressor, custom hoses. Only thing reused is the evap core but it has been cleaned inside and out. Also, how is it distributed?

Thanks for any help,
Jay

**hatzie** · 05-08-2019, 11:16 AM

The GM service manuals have an original system charge for R12 Mineral oil with the original Harrison R4 or A6 compressors. I usually use this volume as a baseline for POE or PAG oil charge amounts.

The Sanden compressor ships with a full reccomended compressor oil charge. If it's leaked out on the shipping box I would contact Sanden or the parts house where you bought it.

Sanden has service information available online and likely has the exact recommended variety of PAG oil for your compressor model number.

PAG is hygroscopic. I don't trust unknown pedigree oil that's been exposed to the atmosphere for any length of time. I would drain the compressor into a graduated cylinder or some other similar liquid volume measuring device and refill with the exact same amount of the Sanden recommended variety of fresh PAG oil that hasn't been exposed to the atmosphere. It doesn't have to be Sanden oil but it should be the same PAG number...

You can get glass graduated cylinders on Amazon pretty cheap. They're handy for accurately measuring small liquid volumes like AC oil and they don't get cloudy and brittle like plastic. They're usually graduated in ML so you'll have to break out a calculator to convert from English to Metric volumes.

Add the difference between the fill on your compressor and the full system oil charge from the service manual to an oil injector and add it after you pull and maintain a full vacuum on the system.

Print an R134a conversion label with the date you converted the system along with the compressor and system oil charge volumes and the exact final R134A charge weight used so you or the next guy don't have to spend several hours fine tuning it next time it blows a seal.

**Wgesnerjr** · 05-08-2019, 01:26 PM

Thanks Hatzie,
Exactly what i was looking for. The compressor I am have is a Sanden "Type" compressor. Not name brand. They do say to it comes with oil but recommends draining and refilling with new oil. Probably for the reason you pointed out; So I plan on doing that.

Thanks Again!

05-07-2019, 01:26 PM	#1
Wgesnerjr Senior Member Join Date: Jun 2015 Location: Atlanta, GA. Posts: 737	A/C PAG oil amount Hi there, I am not near my service manuals but would appreciate some quick help. How much total PAG oil does the A/C system take in a 1985 C10? The system has been fully evacuated and cleaned. New condenser core, Orifice tube, Receiver/Drier, Saden type Compressor, custom hoses. Only thing reused is the evap core but it has been cleaned inside and out. Also, how is it distributed? Thanks for any help, Jay __________________ Jay Gesner Atlanta, GA 1985 C10 Long Bed 4X2 LS 5.3, 4L60E Father/Daughter Project Last edited by Wgesnerjr; 05-07-2019 at 01:37 PM.

05-08-2019, 11:16 AM	#2
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,977	Re: A/C PAG oil amount The GM service manuals have an original system charge for R12 Mineral oil with the original Harrison R4 or A6 compressors. I usually use this volume as a baseline for POE or PAG oil charge amounts. The Sanden compressor ships with a full reccomended compressor oil charge. If it's leaked out on the shipping box I would contact Sanden or the parts house where you bought it. Sanden has service information available online and likely has the exact recommended variety of PAG oil for your compressor model number. PAG is hygroscopic. I don't trust unknown pedigree oil that's been exposed to the atmosphere for any length of time. I would drain the compressor into a graduated cylinder or some other similar liquid volume measuring device and refill with the exact same amount of the Sanden recommended variety of fresh PAG oil that hasn't been exposed to the atmosphere. It doesn't have to be Sanden oil but it should be the same PAG number... You can get glass graduated cylinders on Amazon pretty cheap. They're handy for accurately measuring small liquid volumes like AC oil and they don't get cloudy and brittle like plastic. They're usually graduated in ML so you'll have to break out a calculator to convert from English to Metric volumes. Add the difference between the fill on your compressor and the full system oil charge from the service manual to an oil injector and add it after you pull and maintain a full vacuum on the system. Print an R134a conversion label with the date you converted the system along with the compressor and system oil charge volumes and the exact final R134A charge weight used so you or the next guy don't have to spend several hours fine tuning it next time it blows a seal. __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful. Last edited by hatzie; 05-08-2019 at 01:32 PM.

05-08-2019, 01:26 PM	#3
Wgesnerjr Senior Member Join Date: Jun 2015 Location: Atlanta, GA. Posts: 737	Re: A/C PAG oil amount Thanks Hatzie, Exactly what i was looking for. The compressor I am have is a Sanden "Type" compressor. Not name brand. They do say to it comes with oil but recommends draining and refilling with new oil. Probably for the reason you pointed out; So I plan on doing that. Thanks Again! __________________ Jay Gesner Atlanta, GA 1985 C10 Long Bed 4X2 LS 5.3, 4L60E Father/Daughter Project



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