Thinking of going back to R12 from 134A.
 

My system is tight. I had replaced compressor 3 years ago and been fine on 134A. No leaks and so so cool. I had put in ester oil so I could go back to R12.

How much better cooling should I get? worth the effort and cost??

$0.02
 

Long answer is how deep is your pocket, how much time you have and how competent are you? You have to do it yourself, may be with moral support from this forum as NO shops will touch R12.

Short answer is NO.

There is a post recently on a successful R134 system and all my cars are on 134 with great cooling.

Yea, in San Diego!!! :rolleyes:

I use alternate freons as much as anybody, but still R12 gives you the BEST shot at cooling. Sure, in some climates R134a works just as well, but when you climb into the 90's and above it just won't give you quite as much.
If you have some R12 I would certainly use that over R134a.....

If your car is in decent shape, and your AC system holds pressure well, it may be worthwhile to go back to R12.
I have a pair of 240ds. One had a quickee R134 conversion kit some years ago, and compressor noise & engine load are higher than normal, while cooling on 90+ days is mediocre (though better than nothing) There is a slow leak in that AC and the car is a rustbucket, so no way would I waste my precious R12 on it.

OTOH, I have a really nice 240D, with a replacement compressor, so I gambled some R12 on it and it's been holding pressure for over a year, and system performance is so much better than the AC in the rustbucket.
Now perhaps if I replaced the compressor in the other car, it might perform better with R134, but that car just isn't worth it.

Happy Motoring, Mark

Instead of switching ...
first try cleaning your evaporator fins...
thread by DMorrison shows how bad it can restrict flow... and insulate the unit from the air which needs to be in contact as it passes through...
THEN if that does not really help... think about the other things...

The SD (W126) evaporator is somewhat accessable for cleaning if you pull the blower motor ass'y. I've flushed 'em this way with a water hose which drains via the condensate hose. Have a wet vac and some towels handy for the overflow spills.

You can get very good performance with R134 if you install a >'85 condensor in the W126.

My shop has no problem working with R-12, and it works better than 134a in old systems. There is no reason not to use R-12, that's what the system is designed for. I tried r-134a, I didn't like the performance and converted back to R-12.

here's another vote to switch back to R12.

Every auto shop I know of around here deals with r12. Local NAPA stocks r12.

Here in Central Florida it is freaking HOT!!! The system in my 1985 300d rebuilt with 134a is cool at best! Brand new compressor, Dryer, & wired the electric aux fan to come on when the ac is on. It blows maybe 52 right at the vent. plain and simply not enough to ride comfortably in heat indexes of 100 degrees! AND I have my windows tinted BLACK to fight off the heat rays!
If I can get cooler results switching back to R12 then I'm gonna look into it too!!
I cleaned my evap fins in my other 300d with little to no change in actual results, but may look at doing this one just for grins. It was a easy thing to do and cleaning that crap out from 25yrs of use surely could not hurt!!

(Keep in mind that right now my car has no AC coming from the center vents due to vacuum element being defective but that will be repaired this month!)

What are we talking price wise for the reconversion? 3 cans of R12 and some oil and maybe a charge to the mechanic to vac....$200 total?
If it will give me 10degrees cooler it would be WAY worth it!!!!!

It really depends on the condition of the rest of the system. I'm in North Dallas and have a 450SEL 6.9 that cools great with R134. I had a 560SEC which I personally charged with R12 and it was great until the temps went over 100 degrees , then it was 'eh' at best.

But going back to your question. So you used R134 and ester oil and you want to go back. Then all you have to do is pay someone to pull a vac and recover the system (about $30-$50 at most oil change places) and then charge up with R12.

Can's go for about $20-$25 each and you'll probably need 3-4 cans. So $100-$150 if that's all that you're doing.

One of my favorite Texas sayings describes that situation perfectly: "All hat, no cattle."

first, your 85 should be doing better than 52 at the vent. (not much better mind you, but better than 52..) all the things you have done to the car are good, but you forgo the most important part of removing heat from the car.
the condenser.
it must be clean also.
remove the radiator (heck, do a cooling flush while it's out.) soak the condenser with cleaner from the back. get it VERY coated with degreaser, and bug dissolver and soak the daylights out of it. keep soaking it until you are certain all gunk is dissolved. and rinse it from the back. strong but don't bend any fins.
another thing you could do is get some commercial coil cleaner and soak it in that. pricey at $15 a gallon, but it will get the aluminum fins and coils cleaner than any other cleaner.

I am only stating the obvious.
 

You puriists can stay with R12 for all I care.

I am only stating the obvious. If you can find a shop for the OP to restore it back for cheap then it is fine. Remember, all you can offer is advice or moral supports unless you offer wrenching help. Talk is cheap. May be you A/C experts can pick up a wrench and help.:D

You are obviously misinformed and mistaken.

I can assure you that not everyone shares your fascination with "cheap." The OP already tried "cheap" and has now discovered that it didn't work out very well.

Absolute rubbish.

Bad advice isn't.

If ONLY the OP can be here. Well phrased.

Competent shop and inexpensive are mutually exclusive. How much is inexpensive, $200, $300, $500 or $1K? I find $200 for A/C work is expensive as I have not spent that much on A/C repair doing it myself, even with changing out the compressor.

Did you read my disclaimer, read it at your own peril? May be I am, so beware.

I read the OP again and I did not read that he tried it 'cheap'. Did you have your glasses on or you can read others' mind?

I am sure there will be exceptions that a few shops will touch R12. Why don't you recommend one to the OP, hopefully it is somewhere near where the car is. Don't ask the OP to drive it to your area. That would be disingenuous.

Good advice from you?? That will make my day.

As long as one has either of the standard refrigerants... R12, R134a...
there should not be a problem in normal places... meaning not in the far reaches of the boon docks where there is only one AC shop within a hundred miles.. finding AC service.

If you are satisfied with the cooling capacity, why mess with it. The additional cooling will be minimal compared to the extra cost, especially if the system springs a leak (which inevitably happens). I've converted several cars with no ill after effects. I usually get the air temperature at the center vents to a little above or below 40 degrees, which I'm sure is a few degrees more than factory, but still plenty cool. I'm from an area that gets down to 30 below in the winter and up to 105 in the summer, and I've been satisfied with R-134a performance. I do agree with others that say getting the heat away from the condensor is important in any A/C system.

P.S. I see a good way to start a fight on this forum to to start a thread on R-134a conversions. Definitely not a subject people should be fighting over.

Don't know of anybody in my area that still stocks or sells R-12. Does the NAPA in your area require a license to buy R-12, and how much does a can go for?

Don't you dare. I posted a long/short answer scenarios similar to your reasoning and 'senior' members are all over me.

In Southern parlance, "so so cool" means "not so cool." (Which is completely different than "so, so cool.")

In my opinion, the addition expense of R-12 is a tremendous bargain in the overall scheme of things. In my experience with an '82 300D, the performance improvement when converting from R-134a to R-12 was nowhere near "minimal." "Incredible" would be a far more accurate description.

Since it's federal mandate to have that license, I would assume that they do require it. Haven't purchased it from them so I don't know. NAPA is but one source of r12 for the local shops.

But remember that the test is OPEN BOOK..
can be taken over the internet..
and last time I checked only cost $20...
They just want to know that you know how to read and what some of the rules are...
If you can not pass the test... You should not be dealing with AC stuff anyway...
and always wear goggles when handling any refrigerant work...

Already back-tracking from what is often mis-information from you! :rolleyes: {"Crawfishing" is another term. For Tyler's benefit......} :P

The more I see of your posts regarding AC related issues, the more I am slotting you as either vocally mis-informed, or just one of those "if you don't do it like I do it then you are an idiot" types. {Forced comes to mind. ;)}
Either way, while I don't do everything the same as the more seasoned AC guys do, I at least respect their presentation of the facts for the most part.
You are not garnering respect for your positions. Quite the opposite......

Amen Jimmy.

I am sorry that I mistakenly ' AMENNED' Jimmy's statement..
Clearly Larry is correct...
AMEN LARRY !

R12 is about $10 a pound. I can get easily. Supply is good. Demand is low so supply is high.

Is that in large containers ? or small cans? are those cans 12 ounce and you are able to buy them where the lb price is $10 ?
I certainly think R12 is worth the price for many reasons... just wanted the overall picture to be clear to those who might be needing it...
So many people have this kneejerk reaction when R12 is mentioned.. because at one time several years ago garages were hedging their bets ...or taking advantage of customer's belief that it was expensive and have never updated their ' knowledge/myth ' base....
So please be specific about the sizes and costs... so we can quote this when another one of those ' R12 is too expensive ' people show up in a thread...
Thanks,Greg

LNGFish
 

I live in NC so I know kind of temps and humidity you are dealing with. I also lived in South Fla. and LA (that's Lower Alabama for those out of the loop.)

The statement "R134a works fine for me..." is all well and good from anyone who lives OUTSIDE the southeast of the USA (or places comparable.) What you and I both know is half the comfort factor comes from the dehumidifying ability of the A/C system. It will blow cold but in the South, that is just too weak with 134a in a W123 car. Unless you have a W123 made for the Middle East or Sub Saharan Africa market you have the same design cooling & A/C parts as the European cars. Put simply, the system was engineered for R12, when you put in R134a you reduce the capability of the system.

Please let us know where. My A/C work is picking up and I'm running low.

what parts of the country get -30°F and 105°F in the course of the seasons? what are the humidity levels at that high temp? Here in middle NC, the temps rarely hit 0°F, and Rarely reach 100°F, but the comfort of 134 is almost passable. the temps achieved from the 134 aren't the biggest problem, it's the lack of capacity. the lack of ability to handle idle traffic loads, and highway loads. and it's the damaging effects of 134 to the ancient R4 compressors. look at it this way.
134 must be loaded at 80% capacity of R12. the receiver never fills with liquid. so the txv is always getting spotty flow. and the pressures are higher.
why use it? because it doesn't damage the ozone layer? because it's not a hazzard? oh wait, it's a huge greenhouse gas... it is a smaller molecule, so it will ALWAYS leak out of R12 hoses, so to do it right, you have to change the hoses to coated 134 hoses... so much for a low cost replacement... wait, there's more? oh yeah... the 134 has problems ejecting heat, so a parallel flow condenser is needed... again, far from low cost...
really, why use 134?
12 works,
it's available,
it's low cost compared to the massive expense to do a proper 134 "conversion"
annnnd, R12 works!

[QUOTE=C Sean Watts;2491977] Unless you have a W123 made for the Middle East or Sub Saharan Africa market QUOTE]

Wondering out loud what components they put in those cars?

I get R12 in 30lb containers. I am not interested in the small cans. I did hear from some source that Auto zone or Oriellys can get it on special order and it is in the smaller cans. I have only heard this and I have no proof that this is true. Of course you have to have a 609 certificate to purchase it.

[QUOTE=TchTchr;2491983]Bigger radiators and condensers. I recently got back from Germany - while there, I went to the museum and saw a few models of the 'worldwide models.'

Hey John, do you have any experience with the HC alternatives such as ES12A? They require less refrigerant than R12 for a given system and thus have a lower compressor load which should extend compressor life. I have read that lubrication with ES12A is a problem with the R4 compressor because it is sumpless. I don't really buy that unless I see some proof.

My Canadian spec 450SEL works just fine with R134 in Texas :-). But I agree that maintaining an R12 system is not cost prohibitive.

Mine was converted before I bought it and works so well, I don't mess with it.

Nope.
I only use standard refrigerants.
I can see where the HC's would be lighter on the compressor, but oil flow is extremely important on the R4 compressors. the issue I see with lower vapor pressures is the expansion valve is designed to regulate flow of superheat, and with a low vapor pressure, you could be facing the compressor riding on the frost switch... if the heat of compression is high, with a low pressure point, it would be a good alternative, but it's difficult working with a blend in a leaky system like automotive a/c...

ditto for me.
It is amazing what chances people will take with their equipment..
and how much extra time and money they will risk rather than doing the standard proven thing...
A "NEED TO BE DIFFERENT " ? just contrary ? Don't understand the physics ? I don't know what causes it but it sure seems like a waste of good time and money.

I've been looking for affordable R12 for a month locally, this is the only thing I found so far and it is not affordable.

http://newyork.craigslist.org/wch/pts/1792677653.html

Do you have any? If I can get R12 reasonably priced I will use it.

John, thanks for the answer.

John , have you tried Ebay ?
it does not have to be local ....
just get your 609 (608?) test over the internet... open book, send in the $20 or so electronically, print out your license and put it into your pocket... and when you win just tell them the number.. I got my few cans that way... 12 oz cans...

You recently posted factually incorrect information and almost led another member astray regarding the proper function of the CCU on an SDL, where you clearly know nothing about it.

Now, on another thread, you post additional factually incorrect information regarding the generalized performance of R-134 under conditions that you have not experienced.

If such behavior continues, whereby your posts remain factually incorrect, they're going to be deleted en-masse.

I have the suspicion that your knowledge of vehicle maintenance is extremely limited and that you decide to throw up anything relevant and see if it will stick.

I won't tolerate it here.

Any further posts by you on this thread will be deleted.

$595 seems cheap compared to these guys :eek:


http://www.r22.org/prod_list.php?sci=5

Charlie

I exaggerated a little. It can get down to the negative teens in the winter (not that the A/C is used then anyway), but does regularly get into the 90's and around 100 in the summer. Humidity can be low or high during the summer here. Lately it has been upwards of mid 80's with temps in the upper 80's and low 90's. Temps have been known to change 20 to 30 degrees from one day to the next, or sometimes even the same day. The area I'm talking about is the central midwest, the area between the Mississippi and Rockies.

My retrofits usually include a new compressor, drier, draining of all oil, o-ring changes, and sometimes expansion valve (likely overkill), pressure switch, and valve cores. A higher cooling capacity condensor I'm sure would help much (as this is the biggest change on the OEM R-134a systems), but I don't do that. Have done a couple retrofits with just a drier, pressure switch, and o-rings which also worked. So my cost usually is not that much. When retrofits first were done, it was recommended to replace everything (big $$$), which I think was just a scare tactic. A few years ago I read this is not necessary, and parts such as hoses actually won't leak as theoretically the porosity has been "clogged" by the oil in the R-12. I've also read that the variable orifice expansions valves as used in the older Mercedes are actually better for retrofits than a fixed orifice. I have never found a definitely guide on retrofitting systems.

Just thought I'd add my input based on personal experience on retrofits, which has so far been positive, with no parts "blowing up" due to the conversion and operating pressures staying within reason. If you don't agree, then just pass over my comments. Not here to start a fight. To each his own. The reason I retrofit is due to the fact that cars with R-12 are at least 15 years old now, and with age, leaks develop. I have never had much luck stopping leaks 100%, so I'd rather loose R-134a than R-12. And retrofitting works for me.

You would think that over the decades auto A/C systems would have been changed dramatically to be trouble-free and leak-free, but that still isn't the case. They are not much different than when they first came out, which is really a disappointment given the technology today. I personally think the line connections used today might even leak more with age compared to the old flared fittings. I've seen refrigerators that are 60+ years old and still work good with no problem, but you will never say that with a car.

The argument between R-12 and R-134a sounds like the age-old argument whether Chevy or Ford is better. Have read recently that Europe wants to phase out R-134a for something more evironmentally friendly, so the R-12 saga may happen again someday with R-134a.

R-134a did not replace R-12 because of its efficiency as a refrigerant.

Was discussing this issue with my indy, a terrific MBZ and BMW tech. He's super honest and very fair - ALWAYS!
My concern was servicing my R12 system, it works great now but at 31 years of age it could go on the fritz at any moment, right?

HE SAYS he has quite a few conversions, they just switch out the o-rings, install a new reciever-drier, and charge with R134. You don't have to flush them, the oils mix - that was an old wive's tale - and they work fine. If the system has lost charge then all the oil went out with it anyway.

It's like the biodiesel and stock fuel lines - no need to change them either unless they're already more than a couple of years old. They should be changed every couple of years regardless. Besides, you can't buy a Viton cigar hose anyway.

Some of this stuff gets started and everyone just accepts it as gospel. Sure, there are exceptions, and there are component failures that show up when you start tinkering with these systems.

And some shouldn't be working on their own cars either, the poor guy on the other AC thread doesn't even know what a compressor is. :rolleyes:

I use Ester oil which is for sure compatible with mineral oil just be safe. Here is some retrofit reading material I came across during a quick search just to quench my curiousity. Common points of all documents are to replace the drier and that updating the condensor will improve cooling.

http://www.idqusa.com/faqs.php?c=Retrofitting_an_A_C_System&category_id=14&parent_id=14

http://www.autoacsystems.com/_faqs/detail/retrofit.html

http://www.e38.org/pparish/gm-rp.htm

http://www.e38.org/pparish/gen-rp.htm

http://www.e38.org/pparish/ford-rp.htm

http://www.e38.org/pparish/chry-rp.htm

http://www.aa1car.com/library/retrofit.htm

You are right about that. In the mid '90's, I accepted the notion that R-12 would soon be completely unavailable. Fifteen years later, R-12 is still readily available.

I also accepted the idea that R-134a would work acceptably in a W123. It didn't.

Finally, I accepted the notion that converting back to R-12 was the only way to have good a/c. So I did, and I do.

I don't think that anyone who is knowledgeable about a/c systems would agree with that statement. It's a long ways from being true.

Isn't the internet a wonderful thing? Makes us all a bit smarter, eh? :P

The reciever-drier is a must - it's what collects any moisture in the system and once opened up must be replaced. It's loaded with dessicant, right? So once it gets opened to the atmosphere it absorbs moisture and needs to be replaced.

If the system quit because a seal or a hose leaked, then it can be repaired and recharged with either refrigerant, whichever you can easily obtain.

If it quit because the compressor froze, or it ran dry from some other leak, then it has to be replaced. They don't cost that much, seems a new, not rebuilt one, can be bought for a couple of hundred bucks.

Some of the AC shops I think are preying on the ingnorance of the majority, or they're just not that sharp themselves and so only know to throw lots of parts at it and recharge it. That way they don't have to do it over again because something else in the system acts up once it leaves their shop.

KCM,
"I've also read that the variable orifice expansions valves as used in the older Mercedes are actually better for retrofits than a fixed orifice. I have never found a definitely guide on retrofitting systems."

In speaking about those valves you are mixing types of AC systems... very much oranges and apples... that is why you have not found a guide to retrofitting them into our machines... a fixed orifice is typically used with a compressor which runs all the time.. whereas our systems are ' cycling clutch compressors'.. with the Combo ' block' Txvalve... where the expansion valve is combined with what in other systems would be called a suction valve..