Some of the shops I sell a/c parts too have told me they have gone to Maxi Frig and love it. Never used it myself as I have plenty of 134a. R134a prices have gotten outrageous.

You'll get different responses from different people on what you have to do to convert from r12 to 134a. I know it makes no difference what you do, blow and go is what I've done with mine and they both blow really cold. The folks who say you have to switch oil, change the drier, orings, bla bla bla are full of it.

Nope. I have a can of Freeze 12 unopened. Fits the old style gauges just fine.

Good to know about testing, Joe. I never put anything wrong in, so I can still get some folks to give me a charge. I think they buy the R12 in Mexico and keep it out of sight. I know I see R12 on CL all the time.

Last time I was in TJ (2004), they used one of the substitutes to refill the 911.

I've always done my own work on the AC so I'm not worried about mix and matching refrigerants. :) I just want it COLD.

Doing a search on some BMW sites, there seems to be different thoughts on what it came with.

There's R12 on eBay for $40 bucks a can. I can remember buying it for a buck a can. Should have bought hundreds of them...

According to the auto parts store where I bought Freeze 12 last Summer, the R12 is coming from Mexico in volume. They called it "liquid marijuana." Apparently there's a very big smuggling syndicate behind it.

+++ on propane
 

Use propane on my stuff since 1990 with no problems and runs super cool. Bring your pressures down so as not to freeze up. Don't listen to the BS about having such a volatile solution on board. Those folks should worry more about the 20 gallons of hi-test sloshing around the fuel tank more that the six or seven bic lighters worth of propane behind the fire wall!!

Nope. A regular 1993 Honda Accord. I had to pay for the conversion.

Most newer refrigerants run higher head pressures than their original counter parts... It's sad that we have allowed our markets to become so regulated when countries like Mexico are still pumping out R-12 / R-22 like it is no big deal. Higher head pressures mean less efficiency which means higher fuel consumption which equals more damage to the environment which the newer refrigerants were supposed to protect... blah blah blah lah lah lah its just a scam... a government regulated scam imho...

It does fit a standard manifold... However if you do the conversion correctly you use different fittings for each of the different types of r12 substitutes unique to the supplier.

Amazon.com: FREEZE 12 CONVERSION ADAPTER KIT FOR NEW CARS: Automotive

Duracool Parts and Fittings


Each has it's own unique fittings by law. You're technically not allowed to mix these in with R12 without performing a complete conversion. Besides, why would you want to? These r12 replacements have different system pressures to make them work efficiently. I'm not some advocate for refrigerants, however you would be breaking the law dropping freeze 12 in without the proper fitting switch.



"...charging one refrigerant into a system before extracting the old refrigerant is a violation of the SNAP use conditions and is, therefore, illegal. Second, certain components may be required by law, such as hoses and compressor shutoff switches. If these components are not present, they must be installed.

Choosing and Using Alternative Refrigerants for Motor Vehicle Air Conditioning | Alternatives / SNAP | US EPA

Now Freeze 12 is a bit of an odd one, it's 80% R-134a and 20% HCFC-142b. So running Freeze 12 is not much different from 134a. But this is all academic since Freeze 12 is discontinued, it's replacement Es 12a is just about as expensive as what I can get r12 for here locally.

again.. what you do with your AC in your own garage I really don't care about.

Thought I'd chime in here with a comment and maybe a couple of questions:

My fairly nice '89 325is has a very slow leak (through the evaporator, IIRC) so I've just been charging it every couple of years with R12 at a local shop. Last time it cost about $150, so it's a bit spendy for a 22 year old car worth maybe a few grand.

I'd rather not replace the evaporator ($800) but it is also getting tiresome spending $150 every other summer for R12 and I really like cold air in the summer.

Is there an off the shelf product I could buy to do this myself? Propane? Freeze 12? Something else? Should I have a shop evacuate the remaining R12 before the switch? I'd rather not convert to R134 as that would cost almost as much as replacing the evaporator, and from what I've read, won't cool the car nearly as well.

I'd tell the next owner of any changes I made, of course, but I'm guessing the next buyer of my car would be amazed if the A/C still worked at all ;)

/hijack

I'd advise you to fix the leak.