A/C quantities

[jrobie79]

Does anyone know how much to charge the system up with r12? I replaced all the o-rings and swapped out my condenser, now I want to recharge the system...I have a bunch of r12 cans on hand, so that's not a problem, I just don't know how much refrigerant to add.

Also what is the best oil to use, mineral? How much of that should be added, I have read I should add some to the compressor while the hoses are off, then the rest after the system is all sealed up?

[varg]

According to the Bentley manual, 975g (2.1lbs) of R12, 200cc of oil, back of the compressor on my '91 318is specifies "Denso Oil-6." I don't know what the equivalent viscosity  for that is in mineral oil, but when I did my R134A conversion recently I used ISO46 oil.

From what I've seen put an ounce of oil in the condenser, an ounce in the drier, and the remainder in the compressor. It would be worth your while to have the system flushed professionally or at least buy a pressurized flush-in-a-can, it's difficult to get all of the old crud out of the system, especially if someone before you used stop-leak. Ask me how I know.

[jrobie79]

awesome thank you...I bought a brand new receiver dryer and condenser...I rebuilt my compressor too (all the o rings and seals at least) cleaned everything with pressurized air and lacquer thinner...I am confident the system is clean, and will pull a vacuum on the system for several hours prior to recharing

[benz-tech]

My 134a conversion consisted of replacing a few leaking o-rings and charging the system with 1.5lbs of r134a and a tiny tube of dye oil. Boom, done. 2 years cold now. I hate it when guys overthink that. Since you already have r12 you're good but when the time comes and there isn't any left, just use 134a.

[318lotis]

would love to see a good DIY  ac mod ...