r134 Conversion Parts list ('81 Ponti-Olds)



Site Admin
Feb 25, 2005
Inola, OK
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.


Royal Smart Person
Feb 16, 2009
Western MN
I have had good success doing all O rings/seals, orophice tube, and reciever/drier. The pump doesnt care if its R12 or R134 but anything thats 40 years old is a gamble. The pump might run for years or it might lock up tomorrow. I had 3 years out of the factory R12 pump from my 80 3.8 on R134 before it locked up. Also will need the R12 to R134 adapter fittings as the port on the hoses are different.

Also make sure to use the new syntheic PAG oil so try to remove as much of the old ester oil as possible.

4 seasons sells all their stuff on Rockauto considerably less than what Delco parts cost in my experience.

If you are going to charge the system yourself you need a vac pump to suck the air out along with the charge hose set. It's not a bad idea to buy the hoses if you ever plan to do more down the road and have any confidence in yourself.


Royal Smart Person
Jan 2, 2006
The accumulator- I would use UAC RD5027C. It looks more like original and less likely to leak without so many joints. JMO.

As far as the rest of it, if you're re-using the evap and the orifice line tube from the evaporator (you probably need to reuse the line, don't know of anyone who has it new), I'd be sure to clean them out to remove any excess R12 oil.

You can simply take the amount of PAG oil in the amount you need and distribute some in the suction hole of the compressor, some in the accumulator, and the evap right before you bolt all that crap together. It will eventually mix with the refrigerant, but there's really no need to get an oil injector when assembling a "new" system.

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