Opinions on converting from R12 to R134?

[Zezima]

So I've been doing my research as best I can including reading as many threads as I could on here, and talking to people more experienced and knowledgeable than me and it seems like no one can really agree on what the preferred approach is on this matter, as far as I can see.

Some say keeping everything stock and biting the bullet on expensive old stock R12 cans is the best possible experience, with the con being the financial tradeoff and finding someone who knows how to properly work with an R12 system.
Others say it's not worth it and that converting to 134 is simple and easy, even if it doesn't cool as optimally as R12 and is more fickle to charge properly, with others saying it's not that straightforward and may require upgrading some parts such as the condenser to get it to performing capacity, but considering my general ignorance on the topic I'm not sure who to believe, at least when it comes specifically to our systems with the RV2 compressors.

Of course the "best" route is subjective and ultimately depends on one's goals and limitations, so I'll say for my situation specifically it seems like everything is all there and completely stock, it just seems dry with no refrigerant. Ultimately I would be inclined to go with whichever option is the easiest or the least hassle to restore cold air - even if it's not arctic temperatures, anything would be better than nothing - but it seems like both options in this situation may bring equal hassle one way or the other, either in the short-term with R12, or the long-term with 134, but maybe I just don't understand the options well enough since I don't have the experience, and was hoping people who have done it could shine a light on where to go when you're just trying to make a daily as good as it can be on the lowest budget possible.

Thanks in advance.

 

[Ross Wooldridge]

There is no problem converting to R134A - there's a few steps to follow and you'll be good to go.

1) Make sure that any fittings you crack open when servicing the system have the O rings replaced with proper green O rings. Put on a new receiver/dryer.

2) Replace any suspect rubber hoses with proper R134A spec hoses. There are those that will tell you that ALL the old hoses need to be replaced - that's B.S. The old hoses have enough "seasoning" that they won't leak unless they're already broken. However, any new hoses need to be made with R134A compatible barrier hose.

3) Flush the system really well. Get rid of all of the old R12 compressor oil, as that oil doesn't play well with the oil required for R134A, but again, that's not a difficult task.

4) There are a few other steps such as removing the pressure valve by the compressor, and installing a pressure cycling switch at the temp/pressure sensor bung at the firewall connection to the evaporator, but I have found that many don't even bother with that, and the system works fine.

5) Vacuum the system down to check for leaks - if it holds a vacuum for an hour or two, you're good.

Once the system is prepared to be charged with R134A, the single biggest mistake that people make is to put too large a charge weight of R134A into the system. Start with only 1/2 the original R12 charge weight - for example - if the charge weight for your system is 4 pounds of R12, then put only 2 pounds of R134A in the system. Watch your vent temperatures, and when they level out, then you're good. Typically the weight varies from 50% to 60% of R134A compared to the original R12 charge weight.

 

[saforwardlook]

If you are going to keep the original RV2 compressor, the real issue is where to find a good "rebuilt" one (it seems quality rebuild parts for the RV2s are not available despite some of the claims). No one that I have heard of yet has found a solution to this problem and the higher operating pressure of 134 systems doesn't help this reality. Also if you have a dual a/c system, then rotary compressors generally don't have the capacity to handle two a/c units that the RV2 compressors do.

If you desire a more trouble free a/c experience and don't care about originality of the underhood appearance then the rotary is the way to go with 134 (and you have a single evaporator system). More modern rotary compressors are more quiet, smooth and don't rock the engine around under idle conditions and don't weigh a "ton" either.

Since I saw what was coming in the future to help with eroding the "ozone layer" above the Earth that helps block the ultraviolet rays from affecting humanity that is caused by R12, I bought several commercial jugs of R12 for the future that have not leaked a bit and still are relatively heavy (around 30-40 lbs). That should help me going into the future with the R12 systems and the RV2 compressors. I parted a lot of cars in the distant past and from the many low mileage but rusty ones, I kept the RV2 compressors for the future to help me with the problems with durability of the RV2 compressors, that were known even 30 years ago when I did most of that parting, to have adequate supplies of old but good parts for the future.

Since I value an original appearance underhood, I will continue with the RV2 and R12. If I didn't, going with a rotary and R134 would easily be the best route.

For me at least, this is what the decision is all about in short..........................

 

[volksworld]

my motorhome was the last to use R12...when it needed a compressor (sanden) everyone i could find came pre loaded with the oil for 134...since i didnt want to open a new compressor to properly flush it i went for the conversion...disassembled and flushed everything, new drier, all new hoses , green o-rings etc...end result? not as cold as it was with R12 (yes , not overcharged)....i want the fury to look original so sticking to the RV2, will be rebuilding the compressor myself and it will get R12...but all hoses will be barrier hoses and green o rings in case my supply of R12 dries up and i have to convert later....so in any case my opinion...if you're not a mechanic and dont care about originality ,go sanden and 134...it MAY not blow as cold but should cost less and have less potential for things to go wrong....on a related note went to check the a/c on my sister in laws car...it uses the new R1234yf...$29 for an 8oz can at NAPA...$45 at Autozone...i can buy R12 for less

 

[CBODY67]

Back when the end of available R-12 was happening, I started buying a case of cans here and a case of cans there. Started out that the 1lb cans had 16oz of gas in them. There were also smaller cans, but I didn't buy them. As time progressed, the 1lb cans came with less gas in them, which was marked appropriately on the cans. I had them stored in an indoor closet, which stayed cool. A year or so later, I pulled the case out to check it. It felt light, so I opened it. The reason it was "iight" was that most of the gas had leaked out of most of the cans. Only a few cans had any significant weight to them. YIKES! So much for that "stock pile"!

Allegedly one of the reasons for getting away from R-12 was "can leakage". The can's I'd bought proved that, big time. That was also during the time that R-12 was taxed heavily and such. So, obviously, R-134a was the better long term option for me.

Researching over time about R-134a, it was discovered that "seasoned" hoses can work well, as Ross mentioned. Probably same with the o-rings and such, UNTIL you open that connection, then the R-134a seals and such should be installed. Receiver/drier needs to be changed anyway, as many claimed they had an operational life of about 6 years anyway. Finding one to exactly match the production/OEM size might be an issue?

It was also discovered that the R-134a barrier hose was stiffer and would not make some of the tighter bends the R-12 hose would. So R-134a hose sets made exactly like the R-12 hose sets would not fit, because of that.

Sanden compressors became "the standard" compressor for R-134a and the aftermarket (replacing the older York-style compressor).

I generally liked the Sandens, BUT what I did not like was the way the hoses came out of the back, looking like two "bug antennae" in the process. Later research revealed there were about 14 different "backs" for the Sandens. One of which was termed "GM Back", where the GM hose connection bolted up to it, with HORIZONTAL line exits, or similar. Which to me, would make for a much more integrated/"factory" look of things. With such a horizontal hose exit orientation, spray some satin black paint on the aluminum compressor body, and many would not notice the conversion, I suspect. "Incognito Sanden"?

One other side issue is that an incognito Sanden would not block as much airflow from the carburetor (and all that might mean).

The older OEM compressors were usually in the 10 cubic inch size range. The Sandens are more like 8 cubic inch displacement. With the smaller interiors of modern vehicles, PLUS how much better they are insulated against heat and sound, that smaller displacement seems to work pretty well. So . . . whenever the interiors come out for restoration or otherwise, some DynaMat-type pads for under the carpet or spray on some LizzardSkin? Then some light foam on the back of the door panel boards? and something for the underside of the roof panel? The smaller diameter of the clutch hub on the Sandens will already be spinning it faster, I suspect to help make up for the smaller capacity. Then use a windshield heat shield when parking the vehicle in the sun.

Just some thoughts,
CBODY67

 

[Boydsdodge]

I am seriously contemplating on going back to R12. Looking for seals, and what I should do about flushing what ever might be in the system. I watched the Chrysler master tech AC video, it says to flush system with 5 lbs of AC oil.

 

[Ross Wooldridge]

Why? When butane-based products such as Duracool are available over the counter with zero restrictions?

As long as your system is in good condition, it works splendidly. Just don't overcharge it.

This is a pic of the vent temp teading in my 66 T&C just a couple of weeks ago, using Duracool.

I got the same performance from R134A... but switched to Duracool about 5 years ago or more.

 

[TxDon]

I am in the convert to 134 camp but IMO if you want it to really work well you need to go beyond a simple conversion. I did this successfully on my 66 Monaco wagon with Dual Air but I replaced the compressor, condenser, and most underhood lines. I was also very lucky that both of the original evaporators were in operable condition. Here is my lengthy thread if you are interested:

66 Monaco Wagon A/C Resurrection

 

[3175375]

I am seriously contemplating on going back to R12. Looking for seals, and what I should do about flushing what ever might be in the system. I watched the Chrysler master tech AC video, it says to flush system with 5 lbs of AC oil.

Come back to the (R12) dark side. We have cookies 8^)

I have R12 in my 69 Fury III vert and love it. It has a Sanden type scroll compressor and it works as it should.
I have a stock of R12 cans that I bought from a seller on eBay.

 

[3175375]

Why? When butane-based products such as Duracool are available over the counter with zero restrictions?

As long as your system is in good condition, it works splendidly. Just don't overcharge it.

This is a pic of the vent temp teading in my 66 T&C just a couple of weeks ago, using Duracool.

I got the same performance from R134A... but switched to Duracool about 5 years ago or more.

View attachment 605337

Less than 20 degrees? Really?

 

[Boydsdodge]

Does anyone know about this stuff. I bought it maybe 15 years ago at Carlisle, I think some cold beverages were down and I got talking to a supposed AC pro/snake oil sales tech. I just went through the chem cabinet and there sits 6 cans.

 

[saforwardlook]

The reason vehicle manufacturers don't use the Duracool type refrigerants is because they are flammable. If and when you get into an accident one doesn't need any other problems besides what they already have. If you live in Canada, I guess an accident is less likely than when you live in a major metropolitan area and many different cultures and driver capabilities.

But I would rather go with R12 and I appreciate the warm weather even if driving our old cars is more risky in major cities. I don't need an F350 Super Duty plowing into me as it is and with a flammable refrigerant I don't need that extra issue. A lot of a/c shops won't even install those refrigerants because of the safety and associated liability issue.

 

[Ross Wooldridge]

Less than 20 degrees? Really?

Yes, truth. Keep in mind that it won't do that idling in the driveway, but easily when driving down the road.

 

[Ross Wooldridge]

The reason vehicle manufacturers don't use the Duracool type refrigerants is because they are flammable. If and when you get into an accident one doesn't need any other problems besides what they already have. If you live in Canada, I guess an accident is less likely than when you live in a major metropolitan area and many different cultures and driver capabilities.

But I would rather go with R12 and I appreciate the warm weather even if driving our old cars is more risky in major cities. I don't need an F350 Super Duty plowing into me as it is and with a flammable refrigerant I don't need that extra issue. A lot of a/c shops won't even install those refrigerants because of the safety and associated liability issue.

Definitely something to consider... however, our neglected fuel systems tend to dangerously leak and often are more of a risk in an accident... but that's my opinion, nothing more. And we all know the old adage: opinions are like assholes - everyone has one.

 

[CBODY67]

In some cases the butane-based refrigerants had their "time in the sun" back when R-12 was illegal and heavily taxed. That was then.

Several weeks ago, Scotty Kilmer was using a can of R-152 in place of the y1234a or R-134a gas. Where'd R-152 come from?

One BIG reason to use R-134a is that now, the bulk of shops that do a/c work have the needed recycling machines for R-134a. Most have let their old R-12 machines go to be somewhere else, I suspect. The reason each gas needed its own machine is that the recycling machine is supposed to evacuate the system, clean the oil out of the gas, then put the old gas back in, add new oil to it, and use the on-board gas canister to make up the difference. IF the wrong gas gets into the machine, then "damage control" happens to get things back to where they need to be. As in "contamination" repairs. For the DIY operatives, these things are of little concern, but a later owner might not be that way, discovering that no shop will touch their vehicle with an unknown gas in it, much less a gas for which they do not have a recycling machine for.

Just some thoughts,
CBODY67

 

[saforwardlook]

Yes, truth. Keep in mind that it won't do that idling in the driveway, but easily when driving down the road.

And the evaporator doesn't freeze up??

 

[saforwardlook]

In s"ome cases the butane-based refrigerants had their "time in the sun" back when R-12 was illegal and heavily taxed. That was then.

Several weeks ago, Scotty Kilmer was using a can of R-152 in place of the y1234a or R-134a gas. Where'd R-152 come from?

One BIG reason to use R-134a is that now, the bulk of shops that do a/c work have the needed recycling machines for R-134a. Most have let their old R-12 machines go to be somewhere else, I suspect. The reason each gas needed its own machine is that the recycling machine is supposed to evacuate the system, clean the oil out of the gas, then put the old gas back in, add new oil to it, and use the on-board gas canister to make up the difference. IF the wrong gas gets into the machine, then "damage control" happens to get things back to where they need to be. As in "contamination" repairs. For the DIY operatives, these things are of little concern, but a later owner might not be that way, discovering that no shop will touch their vehicle with an unknown gas in it, much less a gas for which they do not have a recycling machine for.

Just some thoughts,
CBODY67

Good point.

I guess because there are so many older collectible vehicles here in California, there are plenty of shops still around that keep their R12 machines and will even sell you R12 to keep those cars going, but at a price. So there are some positives for large population centers but still plenty of offsets too. That is life.................................

 

[Ross Wooldridge]

And the evaporators don't freeze up??

Yes, but not very often. If they do, I just turn the AC off for a few minutes. Only seems to happen on really long trips.

The other thing I do if I have that concern is to run it on Fresh cool mode - brings in the warmer outside air which keeps the evap from frosting up as fast.

 

[MetalManiacAZ]

Yes, truth. Keep in mind that it won't do that idling in the driveway, but easily when driving down the road.

Oh c'mon Ross. You trying to get one over on us with a centigrade temp gauge? Haha!

 

[Ross Wooldridge]

Lol... I wish, but no, it's for real F°