Quote:
Originally Posted by Diseasel300
The Montreal Protocol banned the use of R12 in 1993 and newer model vehicles. The expansion valve available is a superseded part number that retrofits to the older cars. On 1986+ cars, the coils and systems were identical between R12 and R134a, the expansion valve itself changed (and became a retrofit item) so that the orifice size and power head spring rate were correct for R134a which runs a higher gas pressure and has a smaller molecule size than R12.
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Perfect!, Thank you kindly for your great input, highly appreciated. This confirms That the new expansion valve (retrofit) which I will replace is R134a compatible, for either the early or late cars. Some close up images of the part also show the R134a designation on the part sticker.
You also touched on something that I have been struggling with which is the gas type to use. The molecule size and expansion rate differences between R12 and R134a. I dont want to go back to R12 mainly due to cost and limited gas availability. I have a stock of AutoFrost GHG-X4 which contains 51% R-22, 28.5% HCFC-124, 16.5% HCFC-142b and 4% isobutane (R-600a). This has worked well in other R12 conversions done a ways back that had never been converted to anything other. Also I could just use R134a, you seem to have had great results going that route. Since you know considerably more than I on this matter, do you have an opinion on the AutoFrost vs R134a? Or problems that I might encounter?
I guess I'm at a crossroads because I believe R134a is also scheduled to be discontinued in the US. It is banned in Europe and has become heavily regulated in Canada, leading me to believe that we will see the same here in the US. Do you have any concerns on R134a availability or will it be another Freon-like event like in the 1990's with escalating prices?
Thanks again