R414B is a blend of R-22, R-124 and R-142b with hydrocarbon R-600a (isobutane) added to improve mineral oil miscibility. Not my first (or second) choice for automotive refrigerant.

__________________
95 E320 Cabriolet, 159K

I've converted quite a few vehicles (a couple GM's and the remainder MB's) from 134 back to 12 with a great deal of success. I have just recently converted a '82 300SD to 134 (it was a wreck rebuild) and went with a parallel flow condenser during the rebuild. It seems to be working fine for right now and the pressures were not really that much higher than 12. I would not convert one without going with the parallel flow condenser though.

__________________
Jim

Steve or Larry
I would love to find a 30 lb cyl of GOOD r12 in our area. The cheapest I could find today was $550. I can't justify that much to gain a few deg if my system works fine now. Remember, I said logistics plays into the equation. I totally agree that you need all the cooling you can get. In NC I have not been disappointed with my system even on the hottest days in traffic. I realize I can't win this argument so I will shut up.
Have a great day.

__________________
84 500 SEL (307,xxx miles)

For Canadians that might be reading this, R12 is NOT available any longer, and if your AC system requires service, it must be converted to R134A.

__________________
John Shellenberg
1998 C230 "Black Betty" 240K

http://img31.exs.cx/img31/4050/tophat6.gif

I converted one of my cars, a 1993 Nissan Quest, from R12 to R134a, and it was a disaster.

On hot days the car would cool just o.k. when driving on the highway, but it was less than adequate at an idle or in city traffic.

It was so unsatisfactory that I had it converted back to R12.

Just my $0.02..... (and another $1.98 will buy you a small cup of coffee at Starbucks).

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

pmckechnie,

By taking an online 609, open book test for $15, you can purchase R12 on ebay and you don't have to buy a 30 pound container. You can buy a few cans here or there. 30 pound containers are going as low as $300.

Actually, even to buy it locally you have to have a 609 cert to do it legally.

Have a great day,

At my office I have some old issues of Mercedes Benz Club of America STAR magazine, I was just reading a few hours ago an article about this very subject in the September/ October 2002 issue. A worthwhile issue to buy if your going to convert. or just to learn about the conversion, or stay with R12

Well I'm one of those guys that lives in Canada, Ontario specifically. My 89 420 SEL was converted to 134a, with a new drier, and seems to work fine. Car is black so it gets hot on the outside, but it is cool on the inside. But then again, we had a cool summer.

__________________
1989 420 SEL

Larry,
I have 609 cert and have had it since it was introduced. I have been working on auto a/c for a few years, maybe 37 years (yes I'm an old fart).
Steve says his shop has converted more than a thousand (or something like that) but now says DON'T convert. I wonder if he is going to call all those people and have them come back in so he can convert back to R-12 for free since it was the wrong thing to do? haha
I still say, you should never say NEVER when it comes to conversions.

By the way, thanks for the tip on buying R12 on ebay, but I never buy from a person unless I can see him or her in person. The exception is ordering something from a company I know and I called them, not them calling me. Read through some of the post about things people have bought on E-Bay and found out there are crooks everywhere. I know there is a lot of R-12 canisters out there that have propane or a mix in them. I have seen them. The canisters are original R-12 canisters which have been refilled. Yes this is unlawfull but so is robbing banks but it happens every day.

__________________
84 500 SEL (307,xxx miles)

Cigar,

Yes, in the mild summer climates that you have in Canada, I can see how the marginal lack of efficiency from the conversion will allow your system to cool okay. If you would like to test it, bring it on down to Texas and try it on a 108 degree, 80% humidity day.

Even when they cool well, they are typically short lived as Steve says.

pmckechnie,

I'm sure that Steve had the best interest of his customers in mind when he did all those conversions. It is only AFTER he did them and saw the results, plus seeing the cost of R12 decline that he has come to this conclusion.

Also remember, he and his customers are in one of the hottest climates in the US.

I still am flabbergasted at the reasons for many conversions. For Cigar in Canada, he has no choice if he wants to obey the local law. That's a strong reason. For those who don't have such government invasion into their lives, it costs an extra $30 or $40 to use R12 instead of 134. In order to save that much on refrigerant, people often spend a few hundred or more on other things to make the conversion have a better chance of success. I just can't understand that math. Call me dumb.

I have bought lots of things from ebay and have yet to be burned. There is a system there where you can see the feedback from others who have purchased from that particular seller before. If you pay attention to that feedback you can avoid the ripoff artists.

Best of luck to you both,

Larry,

First I was trying to make a joke about Steve recalling all the conversions. I know at the time, he gave them the best he could at a resonable price.
Both of you are so adament about using R-12 that I am going to see if I can find a few lbs and convert mine back. I will take temp readings and pressure readings before and after and let you know how much difference it makes.
My car doesn't have an A\C sticker on it (it has a newer rad support) so I have not been able to get a definate answer as to how much R-12 it should have. Do you have any information on the quanity. I have Alldata and Mitchell and they give different amounts. 2 indes gave me 2 more answers and the dealer a 5th amount. They ranged from a little over 2 lbs to almost 4 lbs. This is an 84 500SEL with a A-6 Harrison compressor (the best ever built as long as the engine has enough power to pull it.)
It may be a week or 2 before I have time to do the conversion. Customers come first.

Thanks and have a great Memoral Day Weekend

__________________
84 500 SEL (307,xxx miles)

I have read all the above post and find myself in a bad spot. I to converted from R12 to R134 last year after my compressor went out and the new one I bought online was set up for R134. I replaced the reciever/dryer and the expansion valve along with the new compressor, tested it, and then recharged it with 134.
Now my compessor is going out again, I think. just this afternoon it started making noise when I would turn the A/C on. The clutch would engage and then just lock up after about a minute or less. After getting under the car and looking at the compressor, it looks like it might be leaking some mineral oil. But I can't tell from where. It's not like last time where it just blew the seal out of the front of the compressor. It apears to be leaking from somewhere else.
So I guess what I'm asking is, can my compressor be fixed or is it history again? And will this just happen again in a year or so because the system runs at to high of a preseure.
Please help
Shawn
shawnrcisco@yahoo.com

When converting from one refrigerant to another, I've heard it is necessary to change out all O-rings. Does MB use them or only domestics?

Tim

I had to replace my condenser and have my car charged up. In Ontario R12 is not legal for use. The shop that does my heat/AC work is topnotch and has never led me astray in the 10 years I have dealt with them. They only do heat and AC work, on anything that moves. I spoke with Doug about the issues that I have read about on this site and have been reassured that if it is done properly it is not a problem. He got my new condenser, a new dryer, cleaned one switch and replaced another, checked the system for leaks, vacuumed it and then charged it. To date it has worked very well, other than the fact that I needed to replace 4 of my vacuum pods. We have had two periods of extreme humidity with temps in the low to mid 40's, and it worked as well as my Jetta, and better than my Dodge. Perhaps some of the problem systems have not been properly gone over, OR I'm just living life right and mine works.(for now?) Andy

__________________
1987 300D
1997 Jetta diesel
1998 Ram Quad cab

pmckechnie,

Yes, I did not know you were making a joke. Things are easily taken wrong from written text. It's a testament as to the importance of body language.

The chart I have indicates 2.66 pounds of R12 for your '84 500SEL. This is not factory information, but it is probably pretty close.

That said, R12 is not near as fussy about having an exact quantity as is 134. If you get it a little over charged, it will accumulate some in the r/d. If you can achieve about 22 low side and about 250 to 265 high side in 80 degree ambient with a fan in front of the car, engine at about 1500 RPM and after about five minutes for pressures to stabilize, you should be okay.

lyonstexas,

If you change from 12 to 134, you will be better served by using 134 compatible o-rings. These o-rings are good for BOTH 12 and 134. Used to these were green, but now there are 134 compatible o-rings available that are black.

You can get a very good assortment for about$25 from ackits or acsource and it comes with nylog seal lubricant. If you will doing even a small amount of auto air work, this will prove to be a good investment.

Good luck,