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Old 05-04-2003, 03:53 PM
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Location: Santa Monica, CA
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I have heard of R's 11,12,134a,22,290,600a,502,407,406a,even R717; but I have never heard of, nor can I find any reference to, R-145a as a refrigerant used, bought or sold in even a remote consumer connection. Are you sure he said R145a? I he did, I'm wondering........

The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

Last edited by jbaj007; 05-04-2003 at 08:55 PM.
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Old 05-04-2003, 05:32 PM
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i'm going tomorrow to reconfirm the number and try to get a trade name. maybe i got the number wrong..duh..
1984 300D Turbo - 231k....totalled 11/30/07 RIP
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Old 05-04-2003, 11:15 PM
Posts: n/a
There are plenty of posts on using duracool (which I think is better than r-12) but remember there are NO replacements for ANY refrigerants. IE you can not mix any of them. If your system is just a little low then find someone to add a can of r12. If you have a leak and no refrigerant in the system you will have to fix before anything goes in.
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Old 05-05-2003, 09:41 AM
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The shops that tell you that it is illegal to top off an R12 system are violating the law by telling you that. It is a violation of fair trade law and should be reported to the Better Business Beurau. This is spelled out in the 609 certification training.


It TOTALLY amazes me that there are so many people that will go to all lengths and take so many risks instead of repairing their system and recharging with R12.

If your system is requiring recharge, that means that there is most likely a leak. In that case it typically requires some components and work that cost some money. In almost all cases, the cost of R12 at $30 per pound is a small portion of the overall system repair cost.

In many of these cases people are penny wise and pound foolish. To properly convert, the system should be completely flushed to remove the mineral oil because it will continue to outgas R12 after converted if left in the system. Then the filter drier should be changed, ester oil added, compressor rinsed with oil, and on and on. In many cases it is just simpler and cheaper to repair your leak, whatever it is, and recharge with the refrigerant that your system was designed for.

Additionally, the use of all these ALTERNATIVES is ruining a large portion of our recyclable R12.

Don't be penny wise and pound foolish, and if you insist on doing so, properly convert to R134 instead of contaminating our recyclable R12 supply and at the same taking all sorts of risks with flammable refrigerants, blends that cause eventual damage and other problems.

Just fix it, evacuate it and put the R12 back in it!

Good luck,
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Old 05-05-2003, 12:47 PM
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Join Date: Mar 2002
Location: SF Bay Area
Posts: 131
I have to agree with Ockman.

In California it is illegal to handle R-12 without a licence. If you bring your R12 system car to a mechanic for re-charge, it will cost you at least over $100. He tells you first he has to check if the system has a leak. If it does, it must be fixed before he can legally add any R12 into it.

I am glad that I converted my A/C to R134 a year ago (for $39.95) and it is still working fine. I can handle R134 without any licence requirement.


1985 300D Turbo
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Old 05-05-2003, 01:06 PM
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Location: Plano, TX
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You need a section 609 license to purchase R-12 anywhere in the U.S. - that's federal law. Of course, acquiring a section 609 license is trivially easy - much easier than a drivers license, for example. I've had mine for a long, long time - 10 years I think.

Federal law does not restrict your option to top up a leaking R-12 system. Of course, given the cost of R-12, it sure doesn't make much sense to add it to a system with a leak of any significance.

Other governments (state, county, local) may have enacted regulations which do restrict the availability of R-12 and/or the option of topping up a system known to have leaks. This seems happen mostly in left leaning "green" areas, such as Austin, Madison, and places on the left coast. Hence it's difficult to make a universal statement about the legality/availability of bad 'ol R-12.

- JimY
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Old 05-05-2003, 01:16 PM
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Location: Tulsa, Oklahoma
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I didn't heed the advice of the forum members; I let my independent MB mechanic use Freeze 12. The only time my car is cold enough is on a day of no more that 90 degrees F and only if it is running down the freeway at speed. When it had the original R-12, it was at least twice as cold. As soon as I have the money, I'm switching back!

1982 300D
352,000 miles
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Old 05-05-2003, 01:31 PM
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The ONLY way you can switch back with success is to COMPLETELY disconnect everything and flush THOROUGHLY to remove all oil from everywhere. Remove the compressor and flush with mineral oil, dump it out, put in another load of mineral oil and dump that out, turning the compressor by hand with each flush. Then replace the filter drier, reconnect everything with new o-rings, evacuate and recharge.

I hope everyone else is listening to your experience. Moving away from R12 is simply FALSE ECONOMY!


Doing the $39.95 conversion leaves mineral oil in the system and worse yet, often leaves air in the system. A certain amount of R12 is left behind in the remaining mineral oil which outgases from the oil, mixing with the 134. This will set up an acid within the system that will eat it up from the inside out.

As I said earlier, the ONLY refrigerant I would convert to would be 134, but if you want a long term solution, you must flush, change filter drier, compressor oil and evacuate to have a chance for long term success.

Best of luck,
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Old 05-05-2003, 01:36 PM
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Location: central Texas
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Dave, Thanks for sharing....If people are not willing to admit things like that then we have no way of learning from others...

When I started reading your post... and got to the 90degree part.. I immediately looked left at your location... and thought... he is in big trouble... because I know how many Over 90 degree days yall have.... about the same as we do....

Larry, why did it take you so long to join this thread... I was thinking I was going to have to fight the good fight alone.... LOL
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Old 05-05-2003, 02:12 PM
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I was virtually out of computer action for the weekend. I got here as quick as I could.

Have a great day,
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Old 05-05-2003, 02:17 PM
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I was busy working on the 240D. Put me down as being in agreement with leathermang and LarryBible.
Rick Miley
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Old 05-05-2003, 04:06 PM
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Exclamation i got the number wrong.. duh..

should have stated the guy is using R414a as a substitute for R12. says it mixes fine if the R12 remaining in the system is at or less than a 50% charge.
any comments larry or greg-anyone ?
1984 300D Turbo - 231k....totalled 11/30/07 RIP
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Old 05-05-2003, 04:13 PM
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Location: Houston, Texas
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Originally posted by LarryBible


It TOTALLY amazes me that there are so many people that will go to all lengths and take so many risks instead of repairing their system and recharging with R12.


You are implying that those of us using Duracool are in mortal danger.

R-134 is also flammable!!!! In the study course to obtain a 609 certificate from, the document titled "Environmentally Safe Refrigerant Service Techniques for Motor Vehicle Air conditioning Technicians" which advocates the use of R-134 says the following in section 33:

"some mixtures of air and R-134a have been shown to be combustible at elevated pressures. These mixtures may be potentially dangerous, causing injury or propety damage."

I've said this before, Duracool isn't for everyone, but it is a viable alternative to R-12. One needs to look at all the facts and decide for himself.

There is a good discussion a month or so back on the following link:

R12 to R134a conversion kit for 83 300D

Using scare tactics will not help those people looking for information on fixing a problem. And, no, the world isn't going to explode using Duracool.

'82 240D
'87 300SDL
'92 300D 2.5 Turbo

Last edited by airfoill; 05-05-2003 at 04:19 PM.
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Old 05-05-2003, 04:23 PM
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I could not find 414a specifically. I did find 414b. Since 414b is a blend, and most all of those obscure ones are blends, I feel 99.99% confident that 414b is a blend.

There are many downsides to blends, but the most common situation is that in the case of a leak, one component will leak at a different rate spoiling the balance of the blend. This means that the only way to get it in balance again is to empty the system, evacuate and completely recharge.

Additionally most blends have some pretty nasty components. I'm not into using a blend with highly toxic components, most especially in the 124 cars where evaporator leaks are even more common than in most cars. I'm not interested in the risk of having toxic gas in the cabin of my car where myself and my family must breathe.

In my experience, if something looks too good to be true, it probably is. You will always be best suited IMHO to stay with the R12, or if you MUST use an alternate, make it 134 and go through the hassle of converting correctly. It is almost always less expense and trouble to just fix your leak and use R12.

Have a great day,
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Old 05-05-2003, 04:45 PM
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Location: USA
Posts: 8,101
First, there is no R-145a. Check out this list:
Refrigerant Chart

Next, the problem isn't the refrigerant used, it's the oil. Converting an R-12 system to any refrigerant that uses PAG/POE oils is a BAD idea. These oils are junk and require major work to flush out the old mineral oil. Please, if you have an R-12 system, either use R-12 (best choice and often cheapest in the long run), or use a blend designed for mineral oils (like AutoFrost) and label the system clearly (to keep Larry happy, and our R-12 reserves uncontaminated.) Both R-134a and a lot of the blends, DuraCool included, simply don't work at high ambient temps (say, above 95-100F). That's where R-12 and "good" blends like AutoFrost work much better.

I strongly agree with the comment "penny wise and pound foolish", as most of the time conversions work worse than before, and end up costing a lot more than fixing the original leak & re-filling with R-12.

Oh - don't mix AutoFrost with R-12. Bad idea. Read up at AutoFrost's web site.

Good luck,

Boise, ID

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