We did no mods to the systems. We just put in the new 134a. His carried on a bit ..we assumed due to the problems with the mixed compressor oil ..but smoothed out on its own and worked flawlessly until he sold it. I used some "ac-tech in a can" stuff that was supposed to make the mixing of the oils a non-issue.
We had somewhat low expectations out of both. He got the better end of the throwing of the dice. His Neon responded well too. Still on the original conversion fill. His is a 96 ..and I think he's on his 4th or 5th season.
I have no idea how either are configured. I can't recognize a PAV from what I recall they looked like (capillary tube to a metallic diaphragm housing) ..but a whole lot can change in 30 years. Keep in mind I haven't had any formal education in AC since the mid-70's.
When I get flush enough again, I'll have a real conversion done on the minivan. I'm getting to the point, however, that all the hard parts are getting due for failure. Most aren't too hard to replace ..but I don't at all look forward to that evaporator when its time comes due.
