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TOPIC: R12 or R134a

R12 or R134a 22 Jun 2020 22:51 #21326


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It is not clear if my 1984 was retrofitted from R12 to R134a because there is no label attached that I can find.
How else can I tell the difference?
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R12 or R134a 23 Jun 2020 15:43 #21327


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Does your air conditioning blow cold at all? I think an AC shop may have equipment to tell what type the charge is.

The best way to service the unit is to evacuate the charge into a holding tank, weigh how much refrigerant was removed. Wait for a period to confirm that the system holds the vacuum. If not, locate the leak. Recharge based upon weight vs. just relying on pressure.

Quite often in cars our age the Schrader valves are bad, the hoses may leak, and the compressor seals may be leaking. I've had to replace the compressor, hoses and expansion valve on my 1987 928 S4. The AC gets a good workout in the Arizona heat.

If you plan to charge the system with R134A, it may be a good time to change the hoses since R314A molecules are smaller and will leak faster.
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R12 or R134a 26 Jun 2020 10:00 #21336


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I was wondering if one can tell the difference between R12 and R134A ports? If the R12 system was retrofitted to R134A the Low (L) port would be different from the R134A?
I am attaching what my L port system looks at present. The blue cap was on the port and it is simply laying on top of the hose nearby.


IMG_20200624_110048_1593018109251.jpg
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R12 or R134a 26 Jun 2020 11:31 #21337


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Since the hose is the stock hose, you cannot tell what refrigerant is inside. Later model cars that come with 134A will have 134A only connectors.

If the system was upgraded by a professional it should have an upgrade sticker. If not, you just don't know unless a test is performed.
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R12 or R134a 02 Jul 2020 18:08 #21343


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That is a 134a connector. True you cannot always tell, as I am using 134a in my car with the old style fitting, but I am an HVAC guy, and have 134a in a drum, and use my standard refrigeration gauges.

With that in mind, no one would sensibly install the 134a style ports and try to put R12 back in, so I would assume you have 134a in your system.
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