Refrigeration Oil for 1990 Q45 with R12

[Q451990]

So I have a new evaporator from Car Parts Corner on eBay waiting to go into my Q, as well as a new receiver dryer. The problem I'm having now is finding refrigeration oil. The FSM calls for "Nissan (Calsonic) Compressor Oil" - and the sticker under the hood says "Suniso 5GS Oil"

Any thoughts on what should be used?

The manufacturer pointed me to a distributor (Parker) who sent me to a local HVAC supply place that struck out. Specs for that oil are listed below. I have some ancient 4oz cans of R12/500 viscosity Oil on hand. Is all 500 viscosity refrigeration oil created equal?

[Rogue One]

Doing a basic search, I found nothing saying one brand is better than another.

http://www.peachparts.com/shopforum/die ... l-r12.html
I recall on the test...(you might want to confirm this) the oil for R12 is a type of light mineral oil. The PAG and ester oils are more hygroscopic (pick up water vapor) and could cause trouble. You don't need the certification to get the R12 oil, unlike the refrigerant.

Short answer - use R12 oil with R12 refrigerant, ester with R134a. The longer you vacuum pump the system before charging, the better.

Air-conditioning dos and don’ts: Refrigerants and the law
So the oil must be compatible with the refrigerant. R12 systems used mineral oil, but unfortunately mineral oil doesn't dissolve in R134a. So, along with R134a came a new oil: Polyalkylene Glycol—or PAG oil. Note that there is another kind of oil called Polyol Ester Oil (POE).

R 12 OIL R-12, refrigerant, Chargette, 2 oz. R12 & 2 oz. Mineral Oil, total 4 oz
$18.98 Free Shipping

[BCC93QT]

I'm kind of in the same boat. My AC in my 90 actually works. But not exactly efficient. But still blows noticably colder. I live in a cold weather state but still. Not fun with blue leather on a hot day. Debating on just refilling to see how long it lasts.... seeing how 30 years later it still kind of works... or a complete rehab.