R134 and R12

[Nacho-RT74]

what do you know about use R134 gas on our A/C system ?... what have you heard or done about that ?

too many rumours about what to do and don't do or need, but nothing for sure since everybody tells me something different...

[is_it_EVER_done?]

I assume you want to convert to 134, and you get told you need different components by different shops? If that's the case, the different responses may not necessarily be incorrect even though they may be contradictory.

You can do it as simply as draining the mineral oil, and R12 out of your compressor, and fill it with Esther, Pag, or other oil designed for use with 134, then charge the system with 134. The down side is that the system will leak some, and you may get seal failures. This is because 134 is molecularly smaller than 12 and will slowly leak right through the hoses, seals, and possibly other areas that are otherwise perfect seals. It works fine, but is not ideal.

The most complete way would be to replace all the (rubber) A/C lines, drier, and O-rings with 134 compatible components for a leak free system. This will give cooling results as good as 12 while driving around, but will have poor cooling at idle due to the stock (R-12) condenser being inadequate for 134 unless it has a good deal of airflow across it such as driving, or electric fans.

If you replaced lines, seals, etc., You may want to upgrade to a modern parallel flow condenser so that you eliminate the low speed A/C cooling decrease. Of course if you have gone that far, you may as well ditch the heavy, power hungry, RV2 compressor, and upgrade to an efficient aluminum rotary compressor (Seltec, Unicla, Sanden, or other).

You can see why you get differing responses from shops. Of course then the ethics of the shops enters into the picture also, as some suppliers try to sell you an aluminum rotary compressor that is too small for 134, but it works because it is overdriven to make up for the small displacement. This is not a problem unless you hotrod the car and grenade the compressor due to it's over revving, or get some other component(s) that are not up to the task at hand.

Lastly, this question never gets asked by anyone that has a working A/C system (R12 or R134), so I assume yours is broken. If so, you will have to find out why it's not working before you procede with a conversion, otherwise you could end up wasting allot of time and money.

Just from experience, I find that it is usaully cheaper and easier to fix an R-12 system and use 12, than it is to completely convert it to R-134 even though 134 is a cheaper gas. Also, neither gas has any plus or minus as far as cooling ability/performance if the system is set up for it.

I hope any of this helps.

[NHCharger]

I was watching HorsePower TV on The Spike Channel a few weeks ago. They mentioned there was a new produce the you could use in our old R12 systems. Supposed to be completely compatable. I've been meaning to check their web site for info.

[Nacho-RT74]

OK, some tips:

I have an old Mopar mag with that topic about upgrade the original A/C system to use 134. same compressor etc... and they says:

About hoses: needs to be replaced to R134 kind hoses if they were already replaced in the past with new R12 hoses, BUT, if still originals are working they are seasoned enough to keep the R134 smaller molecules working. ( that's my case with Original Hoses ). I want opinions about that.

About O rings... Change them is not a big deal. Just replace black ones for the green ones to 134. just 13 O rings that already found ( except one )

Expansion Valve: They say on mag, that I need a different expansion valve. BUT on a A/C parts dealer told be that is just enough with a special tool ( what I think is just an allen wrench ) turns a complete 360º turn CCW inside the valve on somekind of "piece" that I saw ( like you are opening a water key ) to make it works.

Dryer: On mag stated I need a different one or just replace the interior desicant stuf to 134 gas. two problems on this: I want stock looks and I can't find ANYONE down here that makes that kind of job to replace the desicant stuff inside the dryer. Can I get some problem keeping the same stock dryer ?

Oil... no prob on that is just empty the old R12 one, clean the system and fill the 134 one. Is availablle here and in fact I already have a bottle.

Right now first that I need to do is replace the front Compressor seal, what it has  GIANT leak. A Mopar friend told that is the same than the YORK compressor ( R2V compressor parts are nearly impossible to find here ).

All that I want or wish is opinons about this and what kind of problems you see here.

P.S.: both gases are same cost down here, but I'm thinking on an european Move, not only about cost as the enviromental stuff, that even I have an enviromental enemy car ( LOL ) I want at least help on that.

[is_it_EVER_done?]

Your stock hoses will work. I have never heard of older hoses being less likely to leak, but even if they do, it will only be minimal - maybe a half pound, to pound per summer, so it's not hard to keep the system charged up since you only have to add a little gas about once a year.

If you don't plan to change the hoses, I CERTAINLY would not bother changing out the O-rings. After all, the tiny amount of 134 that will escape through them is probably 1/10th of 1% (guess) of what will pass through the stock A/C lines. Do it if you want, but don't expect to see any difference.

As for the expansion valve, I am not aware of one that is specific for 134. Maybe a better one exists, but I don't know anyone that changed out the stock one when doing the conversion (including myself). Keep in mind that an expansion valve is not ideal for a 134 system, since the operating pressure of 134 changes much more than 12 as the outside temperature goes up, that's why stock 134 systems use an orifice tube expansion block, but your expansion valve will work just fine.

The dryer is another area that will be "good enough". The ones designed for 134 are physically larger, and use XH7 or XH9 dessicant, but there are literally millions of conversions that work just fine with the stock dryer and it's XH5? dessicant. Just make sure you use a new one because the old one is not only full of junk and moisture, but also holds ammonia and other chemicals that will react badly with 134 and it's related oil, which can result in compressor failure in some circumstances.

Regarding oil, Pag oil is the best choice since it is far more forgiving of residual mineral oil, and not as prone to leach ammonia and other deposits. Esther will work, but Pag is better for a 12 to 134 conversion.

For the RV2 compressor seal, I looked up the part number for the RV2, and no York seal part number was the same. I did find that the later model Mopar compressors (aluminum rotaries) had the same seal part number as later Yorks, but I believe you will have to get a seal specifically for a RV2. If you have a Chrysler/Dodge/Jeep dealer nearby, they can order one for you, or here is a link to a suplier  -- http://www.acsource.com/index.asp?PageAction=VIEWCATS&Category=324 -- The seal is quite cheap, so even with additional postage to your country, it is a minimal expense.

When you get ready to charge your system with 134, remember to only put in 80% of the system recomendation (of R-12). much more than that, and you will quickly reduce the A/C performance.

Lastly, did you know that Europe is eliminating R-134 in a couple of years? (2009 or 2010 if I remember correctly). They are going to a Co2 based system, with the US to follow suit, so whatever you do know will probably get changed in a few years anyway, so don't fret over it.

[Nacho-RT74]

Ok... as stated everybody says different stuff. LOL

About compressor front sealer. Bought the York one and install on the R2V... fit perfect hehehehe ... minimun Venezuela-Usa Shipping is around $40 ( on opposite way I think is more ) so, I ended buying the York one, did pay around $12 for it. Let's see how it works.

I don't remember the kind of oil is the one I used. I have the bottle but didn't read. Only read is specifically for R134. I'll check later what exactly is.


Dryer. By the moments will keep the Original... everybody told me it works... but will keep searching for info about that anyway.


about gas ammount... yes, they didn't fill it like R12 since they told me same about different expansion/pressure ( or something )  of both gases.

about eliminating R134 gas... Damn, it looks I'll be on same deal ? LOL... will see on those days then.

Will be great that every body that reads this topic, post opinions and experiences, please.

[John_Kunkel]

The R134 molecule is smaller than the R12 molecule and the R134 will leak at a higher rate given the same orifice, this is why newer barrier hoses are a must when converting to R134.

PAG oil will not mix with mineral oi and can cause problems with residual mineral oil in the system, ester oil will not be a problem if mixed with residual mineral oil.

[is_it_EVER_done?]

John is correct in the 134 oil preference. I didn't realize I mistakenly said Pag is preferable in a 12 to 134 conversion, ESTHER is the best choice in a conversion, not Pag. Sorry for the error. Good catch John.

[Wakko]

is it ever done is right on the money with his post, including the Ester oil usage over PAG.  I've done a number of successful conversions on older cars.   If you do use an R12 substitute, be careful.  Some of the ones designed for home use have propane in them, not such a good idea for a car.  My GN was R12 until the accident...I was pissed as I watched it steam out from under the hood as the line got cracked.   

[Nacho-RT74]

sorry, no specifications about oil kind on bottle, just is for 134a gas. I can say the brand but forgot it LOL, so I'll post tomorrow.

about molecules size, I know that, but on Mopar magazine says that seasoned stock hoses will work perfect just because they are seasoned and will keep the gas. That's why a change only O rings

I think I'll scan the article and post

[John_Kunkel]

about molecules size, I know that, but on Mopar magazine says that seasoned stock hoses will work perfect just because they are seasoned and will keep the gas. That's why a change only O rings

I think I'll scan the article and post

Is it OK if I disagree with "Mopar magazine"?

I have sprinkled stock "seasoned" hoses with leak compound and they usually look like sizzling bacon in a pan, the modern barrier hose will hold R134 better than the old spec hoses; new or "seasoned".

[Nacho-RT74]

yes you can be disagree that's why I started the thread LOL.

anyway I'm just testing, and if Europe will change the 134 stuff, then I'll have to make changes anyway. By the moments my A/C system is working great. Sure time will tell better

[Charger4404spd]

Just a small side note here, I know nothing about a/c, but a friend of mine converted my truck a/c to R134 several years back. He didn't change the hoses or compressor and it still works fine. There has probably been a small amount leaked out, but I can't tell it yet.

I think I heard of a new refridgerant is out now, anyone know what the deal is on that?

[Nacho-RT74]

just went from a buddy's home mine who works with refrigerant stuff to shops... I mean coocks and restaurants refrigerators and freezers and told me about a new gas, yes... didn't remember the number but is less corrosive than 134, needs less pressure and is the new directly substitute of the 12 gas.

Told me abouth the 134 gas stuff that the real problem is on 80s and newer cars with thinner condenser and evaporators lines, made in aluminium. The 134 is very corrosive to aluminium. Our cars made in brass supports that gas.

[twilt]

I will throw in my 2 cents. I am a master tech and have done about 120-150  R-12 to R-134A conversions. I certainly do agree that there is a lot of different opinions. What we techs are required to do at my shop when converting has literally changed every year. After being told to use Ester oil for 8 years, the last seminar i went to ......... recommended using PAG oil in the conversion when doing a typical compressor/accumulator or drier/orfice tube   conversion. The reasoning concerned alleged corrosive nature of ester. While I am not saying that to be true, I can say that our shop had seen a significant increase of lines
and hoses not coming cleanly  off of accumulators (driers) evaporators condensors, etc. after converting them and them returning for either warranty or additional failure work at later dates. (techs like to lube the threaded fittings with refridgerant oil) 

One thing that i think is universally accepted is that you do ABSOLUTELY need to replace the drier. Re-using an old one that has been exposed to the atmosphere for an extended period of time  is simply stupid.   

Here in the U.S. there is a product known as Freeze 12 that is sold as a direct R-12 substitute. I have used it once on acquantainces car and it worked fine as far as cooling. I dont know much about it as far as pro`s/con`s as the shop i work in doesnt allow its use.

On a side note, the shop i work in instituted a policy 2 years ago that required us to replace the condensor on all cars that had suffered internal compressor failure. At the time, most of us techs thought it was just another way to boost profits. Seems we were wrong. Since that policy was instituted, the failure rate of the remanufactured compressors we install has dropped tremendously. ( about 80 percent) Apparently the debris left
in the system as a result of compressor failure was being lodged in the condensors, not being successfully flushed, and ruining the newly installed compressors.

[Nacho-RT74]

Have you ever seen how A/C lines become WHITE because the cold ? Today I saw my A/C lines completely white like a freezer. Firts time in my life that I see that on a car.