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Anyone convert their r1234yf systems back to r134a?

151K views 94 replies 43 participants last post by  Smitty73 
#1 · (Edited by Moderator)
I have a 2015 RT that I repaired after an accident. I had to put a new condenser in it, so I need to recharge the AC system completely. I've found that near me, only the dealers are recharging r1234yf systems, and the price is ridiculous - over five times higher than a 134 system.

After researching, I have discovered that r1234yf is not nearly as efficient as r134a and can even leak out of the system if it experiences long periods of cold weather. In other words, it's just more overpriced EPA garbage. I also discovered that it seems that you can run r134a in the new systems. Most shops won't do it because they would be breaking some environmental regulations, but nothing is stopping a DIYer from doing it.

I am wondering if anyone has done this. I know I have seen posts about people's systems not cooling well anymore - likely due to the leaking systems - so I figured someone out there might have experience with this conversion. As far as the system itself is concerned, it looks like everything is the same except for adding a heat exchanger and a more stout condenser.
 
#2 ·
A fair amount of misinformation there I think..

The cold-weather loss of refrigerant is a non-issue; the fitting caps are designed to prevent that.

The fittings are different, so you'll at least have to use adapters. The next person to work on the system may be surprised.

"r1234yf is not nearly as efficient as r134a" is apparently not true, at least from a quick read of a few industry papers just now. If you were to put R1234yf in a system designed for R134a, it looks like you'd end up with about a 10% loss of cooling capacity, but putting R134a into a R1234yf system would be a wash.

It appears R1234yf oil is compatible with R134a (but not vice-versa), so shouldn't be a problem there.

I don't think you can charge by weight using the same numbers for R134a, you'll have to play the superheat/subcool/pressure game. Not sure about this, don't have time to research.

Expansion valve calibration won't be quite right for R134a, but should be acceptable.

third-party shops are going to have to eventually deal with R1234yf; because very few cars come with R134a anymore. Collision industry rags seem to say that bodyshops were already buying R1234yf gear in 2015, so it should be getting pretty common..

Just my $0.02, and I know I didn't answer the question you asked ;)
 
#7 ·
A fair amount of misinformation there I think..

The cold-weather loss of refrigerant is a non-issue; the fitting caps are designed to prevent that.

The fittings are different, so you'll at least have to use adapters. The next person to work on the system may be surprised.

"r1234yf is not nearly as efficient as r134a" is apparently not true, at least from a quick read of a few industry papers just now. If you were to put R1234yf in a system designed for R134a, it looks like you'd end up with about a 10% loss of cooling capacity, but putting R134a into a R1234yf system would be a wash.

It appears R1234yf oil is compatible with R134a (but not vice-versa), so shouldn't be a problem there.

I don't think you can charge by weight using the same numbers for R134a, you'll have to play the superheat/subcool/pressure game. Not sure about this, don't have time to research.

Expansion valve calibration won't be quite right for R134a, but should be acceptable.

third-party shops are going to have to eventually deal with R1234yf; because very few cars come with R134a anymore. Collision industry rags seem to say that bodyshops were already buying R1234yf gear in 2015, so it should be getting pretty common..

Just my $0.02, and I know I didn't answer the question you asked
Appreciate the info and insight. All things I have read say it is not as efficient, hence the addition of the heat exchanger to try and make up for some of the loss in efficiency.
The reason I'm hearing small shops aren't on board yet is because if the high cost of the new equipment they need and the high cost of the refrigerant - upwards of $68/lb relative to the number of vehicles they see that need AC repairs. Makes sense since it is mostly in cars 2014 and up that have 1234 and vehicles that new aren't going to typically require much AC work. I read an article from a few yrs ago that states that there should be DIY cans out for parts stores by now, but they are nowhere near that yet.
Good to hear what seems to be a confirmation that I should be able to go with 134a in the system. I believe that's what I'm going to do.
 
#3 ·
Sorry you feel the way you do @ the EPA. They are there to protect us from ourselves. I realize it is cheaper to use the R134 but do it right.
 
#4 ·
It is slightly flammable from what I've read...

Otherwise, yeah it's expensive. It's new and what they are producing is going into new cars. They switched because r134a is a greenhouse gas that's way worse than c02 (I'll keep my r134a though!).

Sent from my SM-G935T using Tapatalk
 
#6 ·
Unfortunately I've been around long enough to see the good that the EPA has done for us. We wouldn't have the HP out of these engines that we do without the EPA driving the manufacturers into computers and stricter controls. The air is better even though we have a ton more vehicles on the road than before the rules got put into place. I am just a supporter of them, but I know there are a lot of folks that aren't. That's their choice.
 
#8 ·
You're insane. I have a 292k mile 2001 Ram 2500 diesel with no emissions that gets 19+mpg and an 80k mile 2010 Ram 2500 diesel with all the emissions nonsense that gets 12mpg. You can't tell me that the truck burning that much more fuel to accomplish the same thing is better for the environment. That's just nonsensical. The EPA is a joke.
 
#10 ·
While some people disagree with EPA regulations, hopefully in the long term they are able to help protect the air, environment and human life in general.
I was a truck driver ( now retired ) but used to pick up at the DuPont chem plant in Pennsville NJ. A leak occurred in the Freon processing unit while one of our other drivers was inside. The area was evacuated, but our driver got a good dose of the gas. He never was able to return to work and had permanent lung damage, among other conditions.
Freon is dangerous stuff, to humans and the environment.

I'll take EPA protection all day long opposed to allowing corporate America to wantonly destruct our environment just for profit.
 
#40 ·
I'm a truck driver now and I can tell you from experience that these new DEF systems the EPA requires trucks to be outfitted with are nothing but a money grab. We've got 20-year-old trucks that run perfectly with no issues and yet every single one of the 30 brand new Kenworth's has had to go back to Kenworth to get repaired with less than 10k miles. The EPA isn't the trucking industry's friend nor do they make anything run more efficiently. More maintenance costs do not equal a better truck. If you go look at the original diesel truck vs. a gas engine from the same period then you would find that because diesel engines run leaner they produced far less Co2. There were zero reasons to change the design of the engine besides money. If they wanted to make things better for the environment then they could have just focused on regular cars which way outnumber Semi trucks. Just my 2 cents.
 
#11 ·
Charged my system up a few days ago with 134a and everything works wonderfully. Only had to buy new fittings for my gauge set to fit the 1234yf fittings and the rest was routine. Less than $70, including buying the new fittings. Cheapest 1234 price I got, just to fill and not including mandatory diagnostic charge, was $500. I'll take the $70 fill every time over the other crap. So screw you hippies! ?
 
#14 ·
Hey man,

I don't have a dodge but I have a civic, and I got the new gas as well. I need to replace the condenser b/c Honda warranty does not cover since it got busted by rocks on the road or some other debris.

Anyway, how's your AC doing? Is it still working? My main concern for shooting R134 into the system is the compatibility with the oil.
 
#16 ·
#80 ·
this is specific to the Denso oils, I don't know what Honda puts in their R1234yf systems..

Compressor oil and refrigerant: Mixing old and new - Denso

It is technically illegal to put R134a in a R1234yf system, $2500 fine for individuals.. just so you know.

Make sure you label the system as containing R134a, else some AC tech down the road is gonna be mighty pissed at you.
Actually they wont, if you knew the new systems, the extraction system samples the freon in the system before extracting it and will not extract if not pure r1234yf
 
#41 ·
So long story short my neighbor put 134a in my vehicle that requires r1234yf and now it's blowing hot. It was cold before just not super cold. But now it's hot. So to what I read of your writing, the 134a should be working just fine in my system designed for 1234? At a loss as to what to do at this point because I can't afford to take it to a shop. Do I just need to get a vacuum pump then add the 1234 or what could possibly be the problem seeing as you said 134 should work just fine?
 
#18 ·
Just a fun side note on this topic: when people couldn't get r12 any longer and didn't want to pay to convert their systems to 134a, some geniuses and less scrupulous shops actually recharged their systems with propane... which did work well as an ac refrigerant, until something happened.
 
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#20 ·
I have a 2015 RT that I have repaired after an accident. Had to put a new condenser in it so I need to completely recharge the AC system. I've found that near me only the dealers are recharging r1234yf systems, and the price is ridiculous - like over 5 times higher than a 134 system. After doing some research I have discovered that r1234yf is not nearly as efficient as r134a and can even leak out of the system if it experiences long periods of cold weather. In other words, it's just more overpriced EPA garbage. I also discovered that it seems that you can run r134a in the new systems. Most shops won't do it because they would be breaking some environmental regulations, but there is nothing stopping a DIYer from doing it. Wondering if anyone has done this. I know I have seen posts previously with people's systems not cooling well anymore - likely due to the leaking systems - so I figured that someone out there may have experience with this conversion. As far as the system itself is concerned, it looks like everything is the same with the exception of the addition of a heat exchanger and a more stout condenser.
Don't Buy Cars that Use this New Type of Refrigerant in the AC System see this on you tube.
 
#27 ·
Flawless starts when its below zero/virtually no warming up, not having to smell the car in front of you, actually being able to see across the LA basin, 400+ HP V8's (SAE real numbers, not the bogus numbers from back in the day) that get 24+mpg on the hwy, virtually no maintenance outside of oil changes...yeah I agree advancements in engine management are totally lame. Sure, the EPA and most other government agencies overreach & over legislate after the low hanging fruit is picked just to justify themselves (CARB for instance), but these agencies are a form of competition that force beneficial technological advancements that wouldn't otherwise be pursued by a for profit company.
 
#28 ·
Considering that you get the same 400 hp from an engine 100 CI less, you can't say we get the same HP today as 66. Engines are more efficient and accessories require less HP to operate. Burying your head in the sand because you hate the EPA is not a legitimate reason to ignore the facts. I remember when we had just started to meet smog requirements and the new Dodge CHP cars couldn't catch a car doing 85 when the CHP did a standing start. Now we have 700 HP and more for the street with less than 426 CI.
 
#30 · (Edited)
Another update since I still get messages asking how the conversion back to 134 is working. Well, the compressor locked up about 10,000 miles after changing it over and the entire system had to be changed out. Nah. Just kidding. Several years and over 50,000 miles later, still works like new. And that’s in South Georgia heat. I would have no qualms doing it again.
 
#33 ·
Thanks for taking the risks you've taken on your own equipment and your dime, and posting the results here!! I greatly admire all ingenuity that allows humans to continue to survive in spite of oppressive governments (even their own).
Hopefully, this will buy we consumers around ten more years of freedom, before the next edict blocks us with new snake oil and regulations forcing us to use it at wildly-inflated costs again.
You are an inspiration!
 
#38 ·
You must put the r134 in by weight. Just went through this with my 2006 Jeep Commander with rear ac...replaced the compressor, drier and condenser. The label under the hood says system holds 2.12 lbs r134...exactly what I weighed in. The newly refurbished system puts out 47 degree air...
Looked under the hood of the Dodge that also has rear ac...holds 2.12 lbs of r1234. It's got to be the same system...11 years later
 
#39 ·
So I'm tying to wrap my brain around this....R134A replaced R12 because R-12 was bad for the planet. Now R-1234YF is replacing R-134A because it is no longer environmentally friendly?? You need special equipment to "reclaim the refrigerant before servicing the A/C system", yet when a rock hits your condensor it escapes to the atmosphere. I guess that is calculated risk. Yeah, I guess I'm just too old to understand the politics of it all.
 
#42 · (Edited)
I have a 2019 Chrysler 300 and live in Phoenix. This was the 1st car that I had 1234yf and it was horrible. Be lucky if I got 55-60 vent discharge temps. Shop owner friend talked me into emptied it and put in 134a. Even at 115 degrees sitting in traffic I get nice cold air now. Been in there 2 years now.

Your friend obviously did something wrong. When it's done correctly it is a 100% compatible retrofit. You can't just add 134a into existing 1234yf. All the 1234 needs to be removed, system drawn into a vacuum, proper amount of 134a and PAG added etc. Miss one step and it won't work and possibly damage the system.
 
#43 ·
Hey all you ummm ignorant people out there... The 1234yf is propane. Highly flammable and needing a license to purchase at least in massachusetts. And for the ding ding that was in the building that had a leak poor guy in the wrong place at the wrong time! Shit happens. Epa sux but the idiots that just let the shit out into the air are the shittards. Anyway thanks for the opionens .
 
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