this is a 91 (what's there now, i've not a clue)
what freon system is it running now? what was it and what now? what is the plan?
in 94' this changed.
the orifice is the expansion valve right next to the evap, core. due to small thermal capillary tube stuck in said core to stop freeze up. (icing)
the 2 systems are not compatible, and for sure the oil. (an maybe, hoses and seals) what yours are and what they can stand , no man can answer that.
R12 and R135
btw, kudos for nice effort !
the orig. system shows,
here is a nice GM Corvair post. (my fav car.)
http://corvaircenter.com/phorum/read.php...827,515925
flush out the old
new pag oil or better the ester. universal.
new hoses.
read DR. Fords post, he is very knowledgeable and as we all know a fast moving target, Dupont is constantly trying to make a perfect FREON.
Nothing trivial
and what you can buy on the self is same. (can change at any moment)
and then the R134a.
Basic freon history. 1950s visions...
Freon was invented to avoid the killer ammonia. (like skating rinks use...) and to avoid the CRASH and burn of Propane coolant, but works great. other wise.
but boom you a crispy critter. Freeze 12 hw
Freon was non toxic. if you got a whiff of it. (ask self which would you want the car cab full of , at evap leak time?????) obvious to me, freon.
YMMV
lots of choices, many have issues, see Dr. Ford here.
http://www.stormfront.org/forum/t993641/#post11535998
Freeze 12
some have high flash point, propane.
http://forums.aaca.org/showthread.php?t=...post219961
what most folks want. ????
IT works, if not as good as R12, who cares? ( $100 not a $3500 fix to get best)
and will not kill you.
or leak out.
or trash the compressor.
good luck and cheers !