When to add Pag Oil 46

KLOTCHLEY

MEMBER
1993 MERCURY SABLE
3.8L
6 CYL
2WD
AUTOMATIC
92,000 MILES

Should I add Pag Oil 46 after I vacuum down and just before R134a goes in? I know that my AC compressor is a factory air FS10. I think the Pag 46 amount is seven ounces. My compressor is tagged as a dry compressor. Probably just shipping oil inside. I know I need to dump that oil out and replace with Pag oil. I am worried that vacuuming down might allow Pag oil to escape. So, thus I would put Pag oil in while vacuumed and then add R134a. Oh, this is a complete R134a conversion, except evaporator, on the car listed above GS model. Or does it even matter when I put Pag oil in? As long as its oiled before charging the system.

3 Replies

STEVE W.

MECHANIC
13,555 POSTS

If it is a dry compressor it should not even have shipping oil in it. That is because they do not know if you will be using R134A or R12 with it. As for when to add the oil, add some to the compressor and spin it by hand to get things in it lubricated prior to install. Then pour that out. You need a total of seven ounces in the system. The system is bare at the moment. The best option is to add three ounces to the compressor, and spread the other four ounces around to even out the overall oil charge. So pour some into each hose and the drier until you get to seven ounces.

Then pull the vacuum and add the R134A charge. You will not pull enough oil (if any) out to worry about.
Add R134A until you get to a good system pressure and the cooling you want.