Author Topic: Proper Amount of R12 A/C refrigerant/oil  (Read 1581 times)


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Proper Amount of R12 A/C refrigerant/oil
« on: May 05, 2021, 20:16:52 »
I have a 1969 280SE W111 Coupe, with York 210 A/C compressor, and a Kuhlmeister R12 under dash exchanger.
I managed to get the A/C electrical system working correctly.
The A/C system had zero pressure when opened up, and there was no sign of any refrigerant.
The York 210 pump has lubricant in the crankcase.
I also replaced the drier and the expansion valve.  The valve is wrapped in new A/C insulating tape.
The system held a -30 vacuum for 48 hours, so no more leaks.
I am about to refill the  empty system with R12 and mineral oil. 
How much R12 refrigerant and mineral oil do I add to this system?
« Last Edit: May 12, 2021, 11:45:42 by gcw206 »

Nicolas Aristodemou

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  • 280SL Auto 1970 W113, 380SL Auto 1982 R107
Re: Proper Amount of R12 A/C refrigerant/oil
« Reply #1 on: June 02, 2021, 05:48:22 »
I do not think you can source R12 refrigerant any more. It has been outlawed for some years now. You should clean your system well, replace the filter dryer and install R134 refrigerant. I would say about 700 grams. AC service shops would have a machine that would clean, vacuum check and replace proper amount of refrigerant and oil.
Nicolas Aristodemou
Nicosia - CYPRUS
280SL Auto 1970 US spec (W113), 380SL 1982 R107, Citroen DS23 Pallas 1973, Triumph TR4 1963, Triumph Stag 1973, Mini Cooper S Mk1
1965, Jaguar 3.8 Mk2 1962, VW Beetle 1978 Karman Converible, 1987 Ferrari 328GTS


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Re: Proper Amount of R12 A/C refrigerant/oil
« Reply #2 on: June 02, 2021, 13:35:06 »
I live in Tennessee and I got my 1970 280 SE R12 AC rebuilt with new dryer, York pump and expansion valve and charge two years ago. R12 is out there but it isn't cheap. I was told an R12 based AC blows colder unless you replace all components optimized for a different refrigerant.
1970 280 SE W108.018
M130.980 w/ US emissions
manual column shift


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Re: Proper Amount of R12 A/C refrigerant/oil
« Reply #3 on: June 03, 2021, 00:52:41 »
R12 is still available in the US. Harder to find but available. It is expensive but will cool better than R134 (the most common replacement).  I would definitely replace with R12 as you are planning.  The volume of R12 and mineral oil may be spelled out exactly in the service section of the owners manual (like my 67 w109 is). Also, do you know how much oil is in the york? and is that oil r12 compatible?  If not, consider draining the york and starting fresh with a known oil and volume.  I think there is a drain plug on the side of the york which may be accessible when mounted.