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I have a 1991 420 sel. Ity has R-12 and appears to have a leak in the system. I was thinking about converting over to the 134. A lot easier to get and a lot cheaper. I am going to put in some a/c stop leak and see if it slows or stops the leak. If I have to add some 134 it will be cheaper. Anyone else switched over ..Thanks Ted
 

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I have a 1991 420SEL too just drove home from the beach went inland about 10 miles. 90 degrees out. My R-12 system is worth the extra $$$. It blows so cold.
I dont believe 134 in these cars is as effective as R-12.

My A/c guy agrees. The R-134 is great in the Japenese cars.
 

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Cheaper to fix R-12 than to convert twice R12-R134-R12

I had my "conversion" experience on my 190 16v - I had blown a compressor (shit it happens) and since the system was going to have to be re-done (compressor, drier, valve, triple flush the system) I decided to be "forward" and convert to R134 at the same time.

I wasn't happy with the result - all the correct parts, all the correct settings on the system - but to me R134 just doesn't blow as cold and as "dry" as R12.

I was back at my aricon guy's shop within 2 weeks and converted back to the original R12.

Sure, R12 is more expensive than R134 - but I was unhappy with the outcome on a righteous conversion - and to convert back to R12 (versus driving with a resentment against myself) ultimately was a lot more expensive than to stick with the original R12..

My thoughts now - as long as they keep selling R12 - I won't convert any more of my cars to R134, no way..
 

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R12

Ted,

It depends on where you are located whether you even have a choice. I've been told that if you have "bad" R12 in your system they'll hang you from the nearest lamp post in Australia.

R12 is better for the systems in our cars simply because that is what they were designed for. The size of the compressor, evaporator, condensator were all based on R12, which is more efficient than R134. R134 requires more volume to cool the same quantity of air.

Even if you convert to R134, you will not enjoy lower prices for long. R134 is on the environmentalist's hit list and will soon be as expensive as R12.
 

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Interesting..I just bought R12 for 23$ a lb. Last time I checked R134a was around 10$.. Call me crazy but for 13$ a lb difference is Not worth the savings.

R134a does not work as well, runs VERY high head pressures which on occasion over taxes our older AC components (talk to my friend who's been through 2 evaps on his SEC), perpetually leaks no matter what you do (smaller molecule then R12).

Lastly, if I'm looking to buy a car I look @ 134a conversions as a detractor, where as if a car is still running R12 I'm just that much more likely to buy it.

BTW, before you do a conversion you MUST flush the system...mineral and PAG oil do not make the best of friends..culminating in a very angry compressor!

Jonathan
 

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R134a cant be as cold as R12. I have had my AC going for the last couple of days and I can tell the difference since the retrofit.
 
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Ice Cube Factor

First off R-12 cost about $50-80 per LB at most shops and rising.

Second it does not really matter, the bottom line is that once the system is worked too hard the evaporator will turn into an ice cube. (Seriously).

So you want to tell me just how much diffrence you notice at over $60 per pound? If you can sell me some R-12 for $20.00 a pound please let me know where to buy it!
 

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I bought mine from Pep Boys...

I can get it down to about 15 a lb if I buy in some bulk but this was in the 12 oz (troy lb) cans.


Jonathan
 

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Our cooling systems are tiny enough as it is; putting in a less powerful gas is not going to help things. Mine gets warmer when I sit still even on R-12 - they're such small systems.
 

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Don't get faked out by R12 "imitators"

There are a LOT of aircon products out there now with R12 in the name - and offered as "R12" replacements/top-off's.

The "genuine R-12" can still be bought in the US, and yes it still scares a lot of people off.

The "original-original" was made by DuPont, and other than the 25lb tanks it came in 12oz and 14oz cans.

In the event your aircon guy doesn't have any - or claims its outrageous, a qucik Google can bring it up.. like this non-auto guy with can's to sell.

http://phoenix.craigslist.org/pts/165466906.html

Hodgemaster is 1000% correct on conversions (of course, he's the man) - the lub's for R12 and R1345 do not mix, and R134 runs higher pressure - so blowing out old compressors is like real-real EZ.

I have no complaints about a W126 aircon, 190 aircon's are a bit more limiting.
 

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I will vouch for the higher head pressure! my sel is converted and a i have had to replace the pressure switch twice do to the high head pressures and will probably end up killing my compressor too. The SEC was never converted and blows alot cooler/drier with lower head pressure. My a/c guy charges me 25 bucks a lb for 134a or r-12 so if my compressor does go on the sedan I will convert back over to r-12. if you have a leak in your system I guess it can get expensive but mine usuall takes less than 6 ounces of oil and freon on a yearly recharge. I have also found that evacuating the system and replacing the the receiver/dryer every 5 years keeps everything nice and moisture free. That is assumming you can make it 5 years without having a need to evacuate for other problems.
 

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AxelWulff said:
Ted,

It depends on where you are located whether you even have a choice. I've been told that if you have "bad" R12 in your system they'll hang you from the nearest lamp post in Australia.

R12 is better for the systems in our cars simply because that is what they were designed for. The size of the compressor, evaporator, condensator were all based on R12, which is more efficient than R134. R134 requires more volume to cool the same quantity of air.

Even if you convert to R134, you will not enjoy lower prices for long. R134 is on the environmentalist's hit list and will soon be as expensive as R12.
Quite right. There is a different tolerance level here in Oz. I was able to find a guy prepared to sell me R12 but only after a five minute phone screening to satisfy him that I was a mere Benz enthusiast and not the authorities.

However I ended up using HR12 which pumped straight in and blows blizardly cold. It ended up being a fraction of the cost and required absolutely no conversion. Overall I am very pleased with the product as well as the cost savings.

Good luck,

Brad
 

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fabbrisd said:
I had my "conversion" experience on my 190 16v - I had blown a compressor (shit it happens) and since the system was going to have to be re-done (compressor, drier, valve, triple flush the system) I decided to be "forward" and convert to R134 at the same time.

I wasn't happy with the result - all the correct parts, all the correct settings on the system - but to me R134 just doesn't blow as cold and as "dry" as R12.

I was back at my aricon guy's shop within 2 weeks and converted back to the original R12.

Sure, R12 is more expensive than R134 - but I was unhappy with the outcome on a righteous conversion - and to convert back to R12 (versus driving with a resentment against myself) ultimately was a lot more expensive than to stick with the original R12..

My thoughts now - as long as they keep selling R12 - I won't convert any more of my cars to R134, no way..

WOW! :eek:

Thanks for that info, fabbrisd. I was wondering wether I should convert my 16v to R-134a or pump R-12 back into her. (she had NO freon when I got her.)

I think I'll run R-12 in her, just like my W126. :)
 
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