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Thanks. Tunnel traffic is great, isn’t it. Lol……I bought my compressor from Rock Auto for my 88 R20 454 GMB part # 9712214 and it works OK but would not buy one of those again. Someone on here a while back said that if you run a parallel flow condenser and a blue orifice it will work great. Dont know though. Looks like I have a neighbor here! I live in the Chesapeake Va area. I have a vintage air in my other 88 and it works great as long as the air is blowing on you but it will not cool the truck interior. I was going to have a special hose made for hooking up the rear unit, add some oil and freon and see if I could get it to do the job but have not got around to that yet. Thats #23 on the list.
I followed this post - it was suburban specific. I also added a small pusher fan that helps a little, but the stock clutch fan really moves a lot of air on its own.
the rear fan probably has had the mounting bracket come loose or somebody put it back together a little out of alignment and it is dragging. it's pretty straight forward to dive into it and adjust the position or fix a bracket.
the service manual (see Reference Library) shows how it all comes apart and goes back together.
My rear bracket is all out of sorts. The plastic that everything screws to has gotten so brittle that its just flaking apart. Right now theres just a lot of zip-ties and hopes holding most of it together, although the fan does run freely. Doesn't move much air though, I don't think the ducting is at all tight back there.
When the A/C did work, I would get a nice cold temp back there. Curiously enough, the temps coming out of my front vents would drop by 5-8 degrees when I turned the rear unit on.
Thanks. I bought a new one, so plan on replacing it.make sure the rear expansion valve isn't clogged up before you reassemble the rear system. it should be open at room temp and totally closed at freezing temps.