the valves pretty much tell the story, R-12 is the small thread deal and the R-134 is the wider thicker thread model. That is entirely based on who and what they did when or when not retrofitting the refidgerant.
When I converted my 90 GMC 4x4 I simply evacuated changed the drier and added R-409a and didnt add any stickers cause they dont have freezer conversion stickers. If I would have changed the condensor I would have used 134 (not) to be EPA fluent. But since I used the r-12 condensor I used the 409a, have to overfill it so that the evaporator dont freeze humidity solid. Much colder than the 134 conversion and colder than r-12 but not exactly what was meant when they gave me the certificate on that subject.
doubt that tells your answer but might help, if they retrofitted there will usually be an adapter cap type valve that cannot be removed. If it looks like it makes the threads bigger than its r-134.
Last edited by 632 Regal; 02-20-2004 at 11:36 PM.
94 E34 V2.5+
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