My 1986 745 had the AC retrofitted ro R134a two years ago by a Volvo dealer. Since then it doesn't seem to cool very well, but that is not a very quantitative assessment. Does anyone have a chart indicating the performance specifications for this retrofit? Including for example, relative humidity, outside temperature, ultimate vent temp.

Thanks,
Steve

Durham, NC

I do not think you need to be so scientific. Vent temp on a day in the high seventies sun out, fan at 2 and car moving should go down to at least high 30's, low 40's on a hotter day. Thats what I get on my converted 88 740.
Do you know current high and low pressures?
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David Hunter

David,

You have such a wealth of AC knowledge, I can't resist asking one more question:

I would like to be able to measure the high side pressure. I have found an adapter for the port on the compressor at Advance Auto parts, but installing it would require venting the system (I would have to remove the stem valve). Is there an adapter that allows one to measure the high side pressure without venting the system? (I have a pressure gauge and high side quick coupling for R134a).

-Steve

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1986 745 w/ M46 200K since new, 1995 965 104K

Not sure what you have there. Sounds as if you have an older style R12 fitting on the back of the compressor. If you have a manifold guage set why not just buy an R12 hose for it. When connected it depresses the schraeder valve inside the port.
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David Hunter