interdynamics has a video on r-12 conversion to 134a for 75 and newer models that looks pretty easy but pre 75 requires a special fitting I cant seem to find I'm just not sure if its worth it to keep buying expensive r-12
134a may not be the best replacement. https://www.chemours.com/Refrigerants/en_US/assets/downloads/h75336_Suva_retrofit_guide.pdf
R12 all the way. Its less expensive now than it was 20 years ago. By far the least expensive way to purchase per ounce is to buy a 30lb jug unless you'll never use that much in a lifetime. Working with old A/C systems can be hit and miss an not uncommon to lose or dump the charge to make a repair or fix a leak. Then a couple years later do same thing and you start wishing you had bought a jug. Generally the best deals are found on craigslist or local swap meets but I got a killer deal on a jug full on ebay.
I've been using nothing but R-134 for 20 years now. You'll need to find and fix your leak and it may be a good idea to change to barrier hose. Then flush the system with "flush and clean" and get as much mineral oil out of the compressor as possible. Replace your expansion and POA valves with ones calibrated for R-134. Charge the system and your all set.
GM's VIR systems are best left with R12. There are VIR eliminators for R134a conversions, but you'll have to fabricate a line for an orifice tube and you will still loose almost 10 degrees of cooling.
my 89 chevy pickup did 15 years or better on the r-12 and only needed a refresh so I mixed 1 can of 134a in the system and it stayed cool for 5 or so more years I don't think it mixes it just chases it thru it was 2 cans I think in 5 years ?
I converted the Buchev pickup to 134A when I installed the engine about eight (!) years ago. Since I had to buy a new compressor and have hoses custom made it was no big deal. The big GM axial compressor (which I will replace with a much lighter Sanden-style compressor one of these days) cools the truck beautifully and there have been no problems.
The VIR system combines the expansion valve and POA valve in one unit. You can gut the expansion valve and drop a variable orifice tube into the inlet of the evaporator and your vent temp should be in the low 50s. R-12 and R-134 are totally different chemistry and don't mix. If you do a conversion and it's time to put the oil in do it as fast as possible, R-134 oil absorbs moisture from the air like crazy. If you have a partial container of oil left over throw it away.
1. I'm surprised to see people are able to buy jugs of R-12 on ebay. You have to have a license to buy it, and equipment to recover it if you are servicing a system with R-12 in it. There are some serious fines for just venting refrigerant. I doubt that this is a California-only thing. 2. There are R-12 substitutes available so that you don't have to change over to R-134a. 3. R-134a, as has been mentioned, is not compatible with the oil in a system originally charged with R-12, and vice-versa. 4. The fill valves were purposely made different to prevent people introducing R-12 in a R-134a system. 5. In a truck, I would expect a system converted to R-134a to be fine, as the condenser and evaporator are the same size as you would see in a station wagon, where the interior volume is considerably larger. 6. R-134a has a much lower specific heat content compared to R-12, but a properly charged R-12 system can freeze the balls off a brass monkey, so in an A-body car, making the conversion should not make the cooling unreasonable. 7. R-12 refrigerant oil is also hygroscopic, so unless you have it in a steel can, once you have opened the bottle, use it all right away, or it is garbage.
I run R-500 in my stock Skylark A/C system :3gears: colder than R-12 :laugh: but hey, I stayed at a Holiday Inn Express last night
I hope that the R-152a portion is compatible with your system. Did you vampire some of their refrigerant? :eek2:
As I recall, it was used by Carrier on commercial A/C systems. Something like 20% more capacity than R-12 with a very close pressure/temp chart and designed for mineral oil. It's been a long time since I read the history of it in Modern Refrigeration. Years ago I did service a steakhouse that had 3 10 ton R-500 units, built in '78. It works perfectly in an R-12 car.
so if I buy a vir eliminator I still have to fab a line for an orifice tube or take off original and perform surgery and would the orifice tube simply drop in at the fitting where the expansion used to be located then I could drain the old oil out the rear of comp and fill with some pac-46 ? and how many oz
Here is a link showing all the internals of a vir. http://www.industrialcorner.com/control/car-valves-in-receiver.html Also the vir kit is complete. No need to install an orifice tube. The kit comes with an orifice block
thanks I will buy the elimanator and for 110.00 buy a reman A6 compressor from advanced that is packed with oil and has seals for the 134 conversion then fill it myself with 5.00 cans from wal-mart
I'm not sure that your original hoses are compatible with R134a. I've read that it will permeate. Not 100% sure about this, but you may want to do some research. I had to have a custom A/C hose made for a 76 Eldorado that I was working on. I kept it R12. The local place that builds lines said that I may have a difficult time pushing the hose onto the existing barb because all of the hose that they have has a liner in it so as to be compatible with R134a. As it turns out, the hose went on without having to knock down the high spots on the barb.
I had a guy named Greg Surfas (google him) totally redo my 66 Cadillac a couple of years ago, and he used R-414A. It seemed to work well.
