I use 30wt mineral oil.
It can be purchased by the quart at O'Reilly's after about an hour of convincing the clerk you are not looking for PAG or Ester oil.
4oz in the suction, 4oz in the discharge.

Rotate the compressor by hand a few times to lube the pump for initial startup.
Drier always goes on last and do it quickly with minimal exposure to outside air.
Get a vacuum pump on the system ASAP.
Don't forget new O-rings throughout the system, unless you like adding R12 a lot. LOL

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1991 F250 super-cab 7.3 IDI. (rebuilt by me) Banks Sidewinder turbo, hydroboost brakes, new IP and injectors.
2003 S430 - 107K
1983 300SD - Tanoshii - mostly restored ~400K+.
1983 300SD - Good interior. Engine finally tamed ~250K.
Monark Nozzle Install Video - http://tinyurl.com/ptd2tge

I didn't realize the compressor would hold 8oz. I'll have to make sure to keep the compressor level so none of the oil leaks out.

Should I pressurize the system with Nitrogen before pulling a vacuum?

I could pull a vacuum first, then pressurize and then pull another vacuum.

I'd like to test for leaks on a pressurized system.

Thanks.

pete

Holy cow, you must go to the same O'Reilly's that I do!

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With best regards

Al

The compressor will not hold much oil the way you think. What I mean is to add the oil in the lines after you have installed and sealed the lower compressor connection.

Pressurize with propane. You can make an adapter out of a torch head that will connect directly to your manifold set.

__________________
1991 F250 super-cab 7.3 IDI. (rebuilt by me) Banks Sidewinder turbo, hydroboost brakes, new IP and injectors.
2003 S430 - 107K
1983 300SD - Tanoshii - mostly restored ~400K+.
1983 300SD - Good interior. Engine finally tamed ~250K.
Monark Nozzle Install Video - http://tinyurl.com/ptd2tge

How much bg is in it now? Little will b in the compressor, only 2oz will be in dryer. .did u flush the first time? Don't put in 8 oz. Only put in 3, unless u flush coils.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

I don't know how much is in the system now. I removed the compressor to remove a stripped vacuum pump bolt and then I re-attached the compressor. I did flush the system completely before adding the 8oz of BG.

Maybe I'll just flush everything again. It was mess doing it the first time but it's the only way to know I've removed all the oil.

I'm going to add 8oz of mineral oil. Would you recommend adding any synthetic BG or any other product to the 8oz of mineral oil. If I were to add 2oz of BG, would I then only add 6oz of mineral oil?

I don't have an Oreilly's near me in Balt. MD. I'll have to find some locally. I'll check Advance Auto and Auto Zone.

I see it sold in quarts and gallons. If I buy that much, could it be used a year or 2 later if the bottle was previously opened? Will it absorb moisture from the air once opened?

Thanks for all of your help.

pete

I bought a quart of Tech Select "Wax-Free Mineral Refrigerant Oil fo All R-12 Automotive AC Systems", PN 59000 & 209500 by SMP, Temperature Control Div on ebay a few months ago, ~$12. I will use a butane refrigerant like Duracool, which has worked well for me in several cars for 10 years. Before this, I bought Ester oil at an auto parts, but decided not to use it after I read that it isn't very good (degrades) and absorbs moisture. After adding oil, spin the compressor by hand to insure you won't dead-head it with oil when the engine runs it.

To pump it down, I first connect to a gas car intake, shut that off, then finish with a hand vacuum pump. Since your diesel has a vacuum pump, use that first. The hand pump takes ~2 min to get down to almost a pure vacuum which I let sit for 30 min. It comes up a bit from outgassing, which I pump down and let sit again. Then I introduce the refrigerant and start the engine to flow in more.