r134 conversion parts list


Oct 3, 2018
Inola, OK
repost from GBF bc I figure you guise might know more or at least the same :D

so I'm looking at putting together a parts stash to do an r134 conversion on my '81 Grand Prix, the AC system is literally the original one that came in the car with the Olds diesel. The thing also hasn't worked in literally 25 years. Now I have started looking at parts and part #'s that I'll need and even this guy has a lot of questions....
  • Should I leak test the system before I even get started? I know its leaky. We tried like 20y ago to recharge the system back when you could still get R12 and it wouldn't hold. I would bet that its worse now, and may have introduced corrosion into the system(?) I'm OK with replacing pretty much everything short of tearing into the heater box for the evap core..... Anyone got a decent place to start for leak testing?
  • Assuming its one of my easy accessible parts, what really do I actually need to replace? I've read everything from "everything" to "only the drier and o-tube" (if its not leaking)... I figure I'm in for the hoses, drier, tube, adapter fittings/o-rings, probably the compressor since I don't know if its at fault or not, maybe the condenser bc its 40 yo at this point.....
  • What were the differences in the AC system between model years does anyone know? I initially thought "well I can just look up PN's for my '87 and that should be OK...." Turns out there are a ton of different part #'s involved. Does that just reflect model years or are there other differences like fittings/hose sizes or what's going on there...
  • I know what I'll be "in" for with the parts cost. What else do I need? I figure a r134 bottle, the compressor oil, manifold/gauges, what else? HD vac pump? oil injector pump?
  • 12 oclock vs 9 oclock coil? Guessing that means where the electric plugs in?
Here's what I have come up with so far, from RockAuto .... combined parts list from '81 GP diesel and '81 Cutlass Cruiser 307. Seems to be a similar if not identical setup, but some parts aren't listed for the pontiac where they are for the olds, go figure....
  • Hoses: ACDELCO 1533598 {#19144480, 19191406}
  • O-tube: ACDELCO 155754 {#19189768, 88919511}
  • Misc: FOUR SEASONS 26777 AC System Seal Kit w/ R12 or R134a Retrofit System
  • Drier/Accumulator: GPD 1411326 Tank and Tubes Kit
  • Condenser (maybe): APDI/PRO 7014013
  • Compressor: ACDELCO 1521764 {#19192411} Professional; w/ Clutch
Not the cheapest of parts lists but I don't want to have to mess with this again.... which means I want to do it right the first time.

what am I missing, including the tools I need to do this right. I saw a couple of links and videos that got posted here recently and I remembered that I still need to do this. keep in mind that I'm no HVAC tech but I did take Thermo AND heat transfer in college so that's a start. lol.

Olds 307 and 403

Well-known member
Oct 4, 2018
Melville, Saskatchewan
Pressure it up and see where it leaks. We got away with vacuuming them out, adding leak sealer and changing the compressor oil to one that is compatible. Also jump the A/C compressor, if making a clattering noise, it's time is limited. Also a new orfice tube and receiver/ dryer is a good idea. I am doing that and a compressor in the near future as well, probably when the 350 goes back in my 88 Cutlass.


Active member
Oct 8, 2018
Kokomo Indiana
Change the orifice tube, if it has a bunch of debris on it either the desiccant in the dryer is clogging it up, or the compressor is failing. If the system has been open for a long time, change the dryer.

Maybe you could fabricate some caps for the evaporator core, include a shrader valve to connect a vacuum pump. If the evaporator will hold a vacuum, no leaks. As for any other component, inspect it, if in doubt replace it.

When you do recharge the system, be sure to include the fluorescent dye. If there are any leaks it will be easy to find with a black light