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After the restoration of my 76 442, we put the a/c back into operable running. The shop "converted" it to R134. However, the conversion only entailed sourcing a delco compressor that was overhauled for R134. I pressure tested the stock condenser and it was non leaking. The system was flushed, new drier, and oil for R134.
Since all that was done, the a/c doesn't cool it as one would like a 90 degree day. One guy mentioned putting a bigger condenser on it as R134 needs a larger one to better dissipate the heat. A local shop advised source some R12, he could suck out all the old, and refill R12 and its oil...
Been looking online for R12, but some listings don't differentiate the appliance r12 from the automobile r12 well.
All R-12 is the same, don't matter what it is used for. Just be careful to not buy any of the junk stuff that is sold as R-12 replacement. 134 for sure does not cool as well in a system made for R-12. The guy was correct about needing a bigger condenser. Not sure what metering device a 74 has but if it is adjustable, it will also need adjusted for 134-A.
Just be careful to not buy any of the junk stuff that is sold as R-12 replacement.
If you want to have your system refilled with r12 have your AC tech source the refrigerant. Be wary if he doesn't have any, or is unwilling to do the service unless you bring in some r12.
FWIW, I used r152a (computer air duster) in the AC compressor of my 86 f250 2 years in a row. The first summer it cooled great. The 2nd summer it didn't work, I think I might have another problem with the AC system. If you're having all the work done at a garage this is out of the question, but if you know how to use manifold gauges and want to save some money then I say go for it.
All R-12 is the same, don't matter what it is used for. Just be careful to not buy any of the junk stuff that is sold as R-12 replacement. 134 for sure does not cool as well in a system made for R-12. The guy was correct about needing a bigger condenser. Not sure what metering device a 74 has but if it is adjustable, it will also need adjusted for 134-A.
X2 ^^^^ As stated above do not confuse R12 with FREON 12 (R12 replacement)...
Good luck finding any real r-12. Two of the reasons that I converted over to 134 was because of r-12's scarcity and price. If you can find it around here (Maryland), it's around $200 a bottle.
X2 ^^^^ As stated above do not confuse R12 with FREON 12 (R12 replacement)...
Actually FREON12 is just the trade name for R12. There are subsitutes around that go by a different name such as Hot Shot, R416 and a few others, but FREON 12 is the real deal. I havent priced any lately , but r12 has to be ungawdly expensive. I think its worth it to convert it to 134 a and add the correct size condenser and the right metering devices.
After the restoration of my 76 442, we put the a/c back into operable running. The shop "converted" it to R134. However, the conversion only entailed sourcing a delco compressor that was overhauled for R134. I pressure tested the stock condenser and it was non leaking. The system was flushed, new drier, and oil for R134.
Since all that was done, the a/c doesn't cool it as one would like a 90 degree day. One guy mentioned putting a bigger condenser on it as R134 needs a larger one to better dissipate the heat. A local shop advised source some R12, he could suck out all the old, and refill R12 and its oil...
Been looking online for R12, but some listings don't differentiate the appliance r12 from the automobile r12 well.
Advice?
Look for another solution than R12. I heard somewhere sometime this year R12 is going to go away forever. Not even the professionals will be able to get it.
Let us do some basic HVAC troubleshooting. First, recheck the High and Low side pressures to verify you do not have a system leak or an obstruction. Hopefully, you examined the filter. Did you have the desiccant replaced in the dryer? Verify the clutch is doing its thing. Verify the blend door under the dash is adjusted completely closed when the temp selector is all the way towards cold and the door seal is in intact. This ensures you are not drawing in heat from the heater core.
If all of the above items check out OK, then try a Pilot Operated Absolute suction valve ( or POA) adjustment.
The POA Valve regulates the pressure inside the Evaporator. It is set for R12's optimum pressure of 29.5 PSI(OEM). To get maximum efficiency from R134A it has to be adjusted for lower pressure to take full advantage of the 134a. Looking into the inlet of the valve (through the fitting where the hose to the Evaporator goes), an adjustment screw with a locknut can be seen. Loosen the locknut and turn the adjustment 1/4 turn counter-clockwise, tighten the nut. This adjustment lowered my vent temperatures 9*F from 52*F to 43*F on a 90*F day, (Temps will vary here depending on each system design). Yes, a 134a Condenser would optimize this further but this adjustment should get you cooled down.
The most accurate way to get the POA dialed in precisely is to send it to Classic or Vintage auto air and have them do a bench calibration, but the quarter turn CCW usually does the trick
Last edited by droldsmorland; May 30, 2019 at 05:22 PM.
Look for another solution than R12. I heard somewhere sometime this year R12 is going to go away forever. Not even the professionals will be able to get it.
Went away years ago. You can still get it from individuals that has it around. The price came down on it from where it used to be because the demand is just not there any more. Us old car guys are the only ones buying it. Should never have to pay more than $25 per lb. Well, if the service shop is selling it to you then it will still be really high just because they can and had some.
Went away years ago. You can still get it from individuals that has it around. The price came down on it from where it used to be because the demand is just not there any more. Us old car guys are the only ones buying it. Should never have to pay more than $25 per lb. Well, if the service shop is selling it to you then it will still be really high just because they can and had some.
I'm wondering now what I saw on the news. I wonder if they are going to make using existing stock of R12 illegal.
Let us do some basic HVAC troubleshooting. First, recheck the High and Low side pressures to verify you do not have a system leak or an obstruction. Hopefully, you examined the filter. Did you have the desiccant replaced in the dryer? Verify the clutch is doing its thing. Verify the blend door under the dash is adjusted completely closed when the temp selector is all the way towards cold and the door seal is in intact. This ensures you are not drawing in heat from the heater core.
If all of the above items check out OK, then try a Pilot Operated Absolute suction valve ( or POA) adjustment.
The POA Valve regulates the pressure inside the Evaporator. It is set for R12's optimum pressure of 29.5 PSI(OEM). To get maximum efficiency from R134A it has to be adjusted for lower pressure to take full advantage of the 134a. Looking into the inlet of the valve (through the fitting where the hose to the Evaporator goes), an adjustment screw with a locknut can be seen. Loosen the locknut and turn the adjustment 1/4 turn counter-clockwise, tighten the nut. This adjustment lowered my vent temperatures 9*F from 52*F to 43*F on a 90*F day, (Temps will vary here depending on each system design). Yes, a 134a Condenser would optimize this further but this adjustment should get you cooled down.
The most accurate way to get the POA dialed in precisely is to send it to Classic or Vintage auto air and have them do a bench calibration, but the quarter turn CCW usually does the trick
The desiccant was replaced and correct oil put in the system for r134a. I work at an ag dealership, may have a guy hook up the guages and see what the pressure is reading when the system is kicked on.
I haven't checked the seperator door or seal. Have been using the heater last multiple drives due to cold wet weather and the heat goes good and hot when that adjuster lever is moved.
Guessing that valve you mentioned wasn't adjusted. This is the original system, no orifaces. Asked another shop when we were adjusting the timing, he thought the same thing till we popped the hood and saw the style of the system.
I'm wondering now what I saw on the news. I wonder if they are going to make using existing stock of R12 illegal.
I read a while back that R134A will be phased out in the near future. Instead of outright banning manufacture as was done with R12 back in 1993(?), there will be a HUGE tax applied to discourage its use. So stock up now while you have the chance. I got a 30 lb jug from Sam's Club for $70 a couple years ago and I'm thinking I need to get another one before it's too late.
Another key point everyone is missing here is that you need to be certified JUST TO PURCHASE R12. If not, then you're not supposed to be able to purchase it. Just stick with the R134 conversion, and follow the advice of others above.
.I have a 20 lb Tank for personal stash, it’s for sale at the swaps here in the D. You gotta buy it when you see it. You can’t Ship the stuff. I take my buds r-12 at the nationals in Ohio. I sold a dozen cans last year. It’s out there, I also picked up a charging station and a re claiming station. If your in the D get ahold of me. It’d will make your AC Cold as ice. Lol
stay with what the system was designed for, my ta blows ice cold. I also have my own personal hole in the ozone layer. Lmao.
Fly in For the Packerd Proving grounds show/swap, there’s usually a GM guy there with a stack of it, dont buy rusty cans though, I had a few let go in stg.
I was able to go back to R12 on my '68 last summer. When I bought the car back in '12 it already had R134 in it. The so called rebuilt compressor started leaking from the big case o-rings. The R134/oil combo ruins paint!!! It leaked all over my RH suspension parts ruining all my detail work. I had to pull everything back out, control arms, spring, etc. & repaint it all. It sucked!!! When I took the compressor apart I found it still had the black neoprene o-rings which don't work With R134. This was a newer rebuild from Carquest, you'd think it would have had the correct seals in it these days. Luckily between my neighbor & a buddy I was able to get more than enough R12 to change back. The difference is amazing!! To say it's "ice-cold" is an understatement!!! Just make sure you flush everything out real good & replace the drier.
The AC in my 78 TA was fixed on the Friday of Dream Cruise one year, it was 94 and humid on Saturday, the real day of the event, I had the AC on, it was ICE COLD. I remember pulling up next to a Chevelle, the driver and his GF was Roasted, lol. My GF’s hair was blowing in the AC. They looked at me with a look. Lmao.
heres what I bought off my mechanic when he sold his bussiness.
The AC in my 78 TA was fixed on the Friday of Dream Cruise one year, it was 94 and humid on Saturday, the real day of the event, I had the AC on, it was ICE COLD. I remember pulling up next to a Chevelle, the driver and his GF was Roasted, lol. My GF’s hair was blowing in the AC. They looked at me with a look. Lmao.
heres what I bought off my mechanic when he sold his bussiness.
Those came out in the 90s , about the time of the Montreal Protocol. It was capable of not only recovering refrigerant . But recycling, which means cleaning up the refrigerant before you put it back in. There should be a replaceable filter drier in there to ensure there is no contamination of refrigerant going back in. They were very expensive and heavy to do anything except auto ac .
I read a while back that R134A will be phased out in the near future.
True. Manufacturers are going to change to r1234yf.
I wonder if later model cars will have the same problem finding r134a for their AC in a few years? Does anybody know the pressures for r1234yf? I doubt it would work well in an r12 system.
True. Manufacturers are going to change to r1234yf.
I wonder if later model cars will have the same problem finding r134a for their AC in a few years? Does anybody know the pressures for r1234yf? I doubt it would work well in an r12 system.
As far as I know there is no phase out date for 134a. New chillers are supposed to have something else if they are new by 2024. However these are very large machines. There is still a ton of r11 available and it was phased out in the early 90s.
I'll admit I didn't read through all of these posts but as a word of advisement, they stopped the manufacturing of R-12 over 25 years ago due to it's harmful effects on the Ozone. As for outlawing it, I don't see how that would be useful. For the few amount of people still using it? What do they do with all of the stock piles of it that still exist? They would have to develop a way to separate each chemical, which they most likely already have, but what would it cost? Who's going to profit from it? The main reason R-12 was an issue was junk yards cutting the lines to evacuate the system to separate the precious metals. That was outlawed, but I still see it happen today. I don't think most guys are going to cut their AC lines at $25 a pound. Recycling machines are getting scarce though. Every time one comes up for sale I never seem to have the funds or time to get it. Does anyone remember the IMACA cert. There was a big movement to not sell R-12 to anyone who wasn't IMACA certified. That went no where. Chain stores were selling the small containers, like the 12oz can. I may even have a copy of my IMACA cert someplace. Not even useful as TP at this point.
And speaking of the $25 per pound, it's supply and demand. I remember when it was nearly $1000 for a 30lb cylinder. Now it's roughly $450. Eventually it will become worthless as more R-12 cars will meet the scrap pile. I have friends that swear by 134A but I'll tell you there is no comparison to the cooling effects of R12 when put up against 134A.
2 years ago I pulled a 100lb cylinder of it out of a basement in the Bronx. We pulled at least 30 cylinders out that day, propane, O2, acetylene and 1 was R-12. That one cylinder I had put aside and low and behold someone had the bright idea to mix it in with the others. Unfortunately there's not many people outside a Haz Mat unit that know what Dichlorodifluoromethaneactually is and it was picked up by the gas contractor the city uses.
This weekend I went to NAPA to get an intake manifold gasket for my Olds. They were having a 20% off parking lot sale. I browsed quickly as I was waiting for them to pull my part from the warehouse and I noticed a set of manifold gauges. They were for r1234yf!
Ok, now you have to show us a pic of your Pontiac. Is it a Burt Reynolds Trans Am like the one in your avatar? Does it have an Olds engine? Better include a pic of the AC compressor (engine) so we aren't thread hi-jacking.
Here, 400 Poncho motor, 78, Y88. Note the OG Compressor. Lol My AC was not working for years, when I found my mechanic we went through it, it had a bad o ring where the line joins at the core support, plus I broke a tang off the low pressure switch, that needed to be replaced, and it needed the probe thing, so I found the part and bought 2. The accumulator is after market, my mechanic wanted a new one one when he went through it, I did save the OG one to rebuild sometime. AC clutters up the bay, but when it’s hot it’s nice.
Dang, I put 2 pics up. Only one posted. Here’s the missing pic,
next to it is my 95 Q 45. 300 hp, rear wheel drive all alum motor, fun car to drive, I stomped on a Honda with a big wing on the back one day, lol. I yelled at the guy, V8. Lmao. The motor is a work of art on the Jap car.
