924Board.org

[austinporsche]

Hey, it's getting warm here and the AC on the 924 I bought about 18 months ago is a little weaker than last year.

Suspecting maybe I have a leak, but before I evacuate the expensive R12 (and then fill it with more expensive R12), I was thinking that maybe it's time to upgrade to R134.

I have successfully fixed AC systems in probably 10+ vehicles (including a couple of dual front-rear evaporator minivans) but never an R12 system so I wanted to get an idea of what's involved in a conversion (I have an '82 RX7 and 73 'vette also with R12).

Is it:

Compressor
Compressor + expansion valve
Compressor + expansion valve+condenser
Compressor + expansion valve+condenser+evaporator
Compressor + expansion valve+condenser+evaporator+plumbing

Any insight/advice from anyone who's been there, done that would be appreciated.

[Ozzie]

The oil used in R12 is not compatible. This gets into all the rubber bits, hoses and seals and the dryer tank.
Once they are replaced and the system washed out it might be ok.
However, IIRC the gas operates at a different pressure so other changes , tx valve and compressor for instance, may be needed.
The evaporator and condensor should be ok after a flush
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

[austinporsche]

Figured I'd have to do a flush forgot about the receiver/dryer.

And the o-rings as well.

Maybe the R12 isn't so cheap after all . . . .

[morghen]

You cant get R12 in Europe anymore, pollution norms...maybe in USA you still can. If you cant, then there is a replacement for R12 that is sold now and it works.
I had my 931 filled with the replacement for R12 and it not only worked great it also held well.
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[austinporsche]

you mean the R12a -- that's what we call the replacement in the US.

I understand it's propane based.

You can still get R12 in US, just 6-10x more expensive than R134 (R12a about 2-3x more expensive than R134).

So it's worked for you then?

Mixed reviews here in US.

And I need good efficiency as I live in Texas, so the AC has to take 37-40C down to 23C to be anywhere near comfortable.

[morghen]

No, i dont mean R12a, there is a modern product aimed specifically at older systems and its not called R12a. I cant remember the name now.
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[austinporsche]

If you can find the name, that would be great because I am not aware of any such product here in the US other than R12a.

[safe]

[morghen]

If you can get R12 then get R12, its by far the best option, the system will work best with R12.
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[TJC]

Unless you convert the entire system I would suggest you stick with the R12. If your system is "weak" but still working now perhaps you could add a dye first before you evac and recharge. Then if you find a leak you can repair it and then do your evac and recharge and it will probably be good for another 30 years!!! Leaks are normally caused by the little o-ring seals and are easy to repair.
Here in Arizona I've bought cans of R12 for as little as $25.00/can just a few years ago. Subtract the cost of the same amount of R134 you need plus the cost of some dye and maybe some O-rings compared to conversion and see what is a better deal. Plus in my opinion the R12 cools better than a converted to R134 system.
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'87 Porsche 944 NA... "Liebchen"
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'04 BMW X3..."Xander"
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