I have a 91 300SEL W126 chassis. It has R12 freon which is running low. The compressor works fine, and i think it is just a slow bleed from somewhere b/c freon has not been filled in at least 7 years. I do not want to change out the compressor, etc. Any pearls on the R12-R134 conversion kits available at AutoZone, or the hydrocarbon based kits available on-line???

Before you go out and spend yer money on conversion you might like to read this!

Smokie

http://autorefrigerants.com/

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so what are you recommending...
The r12 or the freeze 12 hydrocarbon based refridegerant???

Also, I thought purchasing R 12 was illegal in US

This issue comes up from time to time around here(I am pretty new around here) and from what I have heard the conversion to R134 is a bad idea for YOUR car, (and other Mercedes too), the R134 does not cool as well as the R12, and could eventually damage some of the hardware - not sure exactly which bits.. or how, but remember the components were not DESIGNED to handle R134.

I haven't heard that R12 is illegal - at least not lately, but I could be wrong there, other owners will need to set you straight on that one.

Mercedes Benz recommends certain fluids for their cars, and I wouold tend to take faith in what they recommend.

Proceed with caution, and search the archives for threads on this subject before proceeding.

.03

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1995 E 420, 170k "The Red Plum" (sold)

2015 BMW 535i xdrive awd Stage 1 DINAN, 6k, <----364 hp

1967 Mercury Cougar, 49k

2013 Jaguar XF, 20k <----340 hp Supercharged, All Wheel Drive (sold)

What's illegal is converting from R12 to hydrocarbons. Also, hydrocarbons are illegal is several states (but not federal).

It is illegal to make or import R12 in the USA. But that doesn't mean you can't buy it. You need to get a license. You can get it online for very little money; search here for 609.

Note that it's not even illegal to add R12 to a leaky system, but it is illegal to vent any automative refridgerant, even hydrocarbons. I believe that it's illegal to vent any refridgerant, although it appears to be legal to vent 134a which is sold and used for non-refridgeration purposes.

While it's not "per the book", a leak that takes 7 years to get a little low (compressor still runs) would prbably respond well to a recharge (with gaugeS). Get your 609 certificate, a buddy that knows a little about A/C, a couple of cans of R12 from Ebay and read here:http://acsource.net/acforum/index.php?sid=167da32d8a79d9c298ac568cf8cf5672
and here:http://www.autoacforum.com/

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The Golden Rule

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

I guess if I had a R12 system I would be looking at the Freeze 12 . Which I believe is compatible and the way I read works better than R134. I don't think there are any legal hassles with Freeze12



*
Why should I retrofit an R-12 system with Freeze 12 instead of R-134a?

1. Freeze 12 will cool better than R- 13 4a in most retrofit applications.

2. Freeze has a pressure curve which is close to R-12 while R-134a operates at significantly higher pressures than R- 12.

3. Freeze 12 works with the existing mineral oil and does not require lubricant replacement as R-134a does.

*
Why should I buy Freeze 12 instead of one of the other alternatives?

1. Freeze 12 will be competitively priced compared to the competition.

2. Freeze 12 has been thoroughly tested and shown to be an effective replacement for R- 12.

3. Freeze 12 is expected to have excellent distribution nationwide to insure that it is available for the consumers car wherever they may need service.

4. TCC has been in the refrigerant business for over 30 years with the expertise
and knowledge to provide this product to the marketplace.

*
Can I use Freeze 12 in non-automotive applications?
Because of the license agreement on this patented product, TCC can only sell it for automotive use. TCC is Technical Chemical Co. and is the manufacturer of Johnsen Products/Freeze 12.


Smokie

__________________
95 E420 BigBlue
500E Sway bars
2001 C Class 16 in. Rims
KYB Struts and shocks
Rear spoiler
American Stitches Wheel
Bigred 99 F250 Powerstroke
JVC EXAD Mp3 player
JVC EXAD GPS

The most obvious question is missing: Why change to Freeze 12 instead of staying with R12?

It is a bit more expensive than the substitutes and requires a EPA 609 certificate (easy to get certified) but here are the reasons I would put forth:

1. The R-12 substitutes like freeze 12 and especially the hydrocarbon formulations are composed of multiple substances and have a tendency to fractionate over time which changes the pressure/temperature characteristics if you have a small leak.
2. Any refrigerant other than r12 or R134 is not mainstream in the sense that A/C repair shops do not generally use alternative refrigerants and may not service systems that are charged with them
3. Using R12 means you do not have to flush or change out any of the original components
4. The system was designed to use R12

Do some due diligence and especially do not take any of the marketing boilerplate from the alternatives at face value.

If you do choose to charge with the R-12 alternatives, be sure to have an A/C shop evacuate the remaining R-12 and not add the alternative to make up the charge.

First, go here:

http://www.epatest.com/

Pay the ~20 and get the 609 certification. Its open book and not that difficult.

Next, go here:

http://store.lenzdist.com/

and buy a couple 12 oz cans of R12 along with the proper gauges.

Do it right the first time, you'll be much happier.

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