Automotive Air Conditioning Information Forum (Archives)

Provided by

We've updated our forums!
Click here to visit the new forum

Archive Home

Search Auto AC Forum Archives

oil capacity and type

LarryP on Tue March 18, 2008 9:53 AM User is offline

Year: 1993
Make: Pontiac
Model: Bonneville
Engine Size: 3800
Refrigerant Type: R12

Good morning.. I am doing a frame-off resto (if there is such a thing on a unibody) on this Bonneville. I am putting it back to R12, I have the original pipes/hoses in great shape, I saved them from when I retro'd it to 134A. I did the retro myself 70K ago when black death occurred. So far in the restoration, pertaining to the AC system, I have flushed and dried and reinstalled the evap. New condenser ready to install. Compressor is fine, plan on flushing it and reinstalling it. Changing all o rings. Question: what type of oil was in that system from the factory with R12, how much oil should I put in the system, and how much in which component.. Thanks.. Larry.

TRB on Tue March 18, 2008 10:47 AM User is offlineView users profile

Oil capacity for that vehicle was 8 ounces. 500/525 viscosity mineral oil was used with R12 refrigerant. 6 ounces compressor and 2 accumulator would work for me.


When considering your next auto A/C purchase, please consider the site that supports you:

LarryP on Mon March 24, 2008 8:56 AM User is offline

Ha, I just found the chart on this website for the capacity.. sorry about not rooting around more before I asked. But, 6 ounces in the compressor? I find it hard to beleive I'm going to get that much in that compressor while it sits on my bench... and certainly gonna be tough once it is bolted to the engine.. Is that correct? Thanks... Larry.

JJM on Tue March 25, 2008 12:29 AM User is offline

You don't have to get it all into the compressor... get a few ounces in the compressor, enough to get it bolted in without making a mess, then dump the rest anywhere else in the system. One the compressor starts the oil will circulate as it's supposed to.

No mention of it, but you should replace the accumulator, and any lines with mufflers or filters since those can't be successfully flushed. You might want to consider replacing all the hoses at this time as well... after 15 years they're likely on borrowed time, especially high side lines.


When considering your next auto A/C purchase, please consider the site that supports you:

LarryP on Thu March 27, 2008 8:37 AM User is offline

Thanks for the reply.. But, I have another question.. This car was converted to R134a about 50K ago, the AC system was working great when I took it all apart. And yes, I have an accumulator brand new ready to go, and new lines, and all new Orings and such. So, the only things original in the "plumbing" section are the evap (which was removed, cleaned with mineral spirits, compressed air dried, reinstalled) and the compressor. The oil for the R134a had green dye in it, so last night I ran some mineral oil into the suction, then turned the compressor by hand to pump it out, and repeated this until hopefully the oil ran totally clear (free of dye, therefore free of all the old oil) A full quart later of this, and there is still, I think, a slight shade of green, telling me I still have some of the old oil in there. wow, after 32 ounces of flush, what else can a guy do? Or should I even care at this point? thanks. Larry

GM Tech on Thu March 27, 2008 11:04 AM User is offline

Those compressors were sent to the factory with the entire system charge in them-- so I know it can be done- 8 ounces fits into the compressor- so putting 6 in it is not a problem- the easiest way is to pull a vacuum on the high side and suck it into the low side on the compressor.. works every time.........

The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

mk378 on Thu March 27, 2008 11:20 AM User is offline

If it's PAG in there you have to get every drop out before running R12. Uncapped PAG turns to sludge when R12 hits it. Ester oil would be OK to leave some in, or run instead of mineral oil altogether.

LarryP on Thu March 27, 2008 11:59 AM User is offline

Thanks for the reply.. Is there a way to determine what type of oil is in there? It was a long time ago when the retro was done, I don't remember.. but it is probably the okay stuff, since it was a retro..
If in doubt, can I flush that compressor with some type of solvent without wrecking it?
Or, I have another compressor of unknown age, it came on a parts car that had a non-functioning but fully charged and non-black deathed R12 system... the clutch was shot..
I'd rather use the compressor I'm messing with, just because I know its age, etc.. How shall I proceed? thanks, Larry

LarryP on Thu March 27, 2008 3:16 PM User is offline

Well, forget the question about flushing the compressor with something other than oil.. I've been rootin' around on this website, it's been a while since I've done AC work, last time was installing central air in my house in 1999.. Either way, let me rephrase my questions.. If a retro had been done years ago, and I'm sure I went off the advice of someone professional, would I have used pag or ester when I did it? And if I wanted to be ultra sure of a clean compressor, how should I flush it - last night I poured oil into the suction port, turned the compressor over clockwise, lotsa gurgling and such, pumped it out of the discharge port in spurts, then repeated until a full quart was used up. FWIW, never got any junk out of it, clean as a whistle except for the green dye.. Suggestions? Larry.

TRB on Thu March 27, 2008 3:38 PM User is offlineView users profile

Sounds like you have run enough oil through the compressor to clean it out enough not to have concerns. I would suggest using the BVA Auto 100 now as it is good with both R12 & R134a. Heck you can even have traces of PAG and the BVA will still work well with it.


When considering your next auto A/C purchase, please consider the site that supports you:

Back to Automotive Air Conditioning Forum

We've updated our forums!
Click here to visit the new forum

Archive Home

Copyright © 2016 Arizona Mobile Air Inc.