Picked up my room AC unit from my refrigeration guy and got him talking about automotive AC's.

Told him I am putting together the system in my '84 244GL and would he draw a vacuum on it once I am ready.

"What kind of refrigerant will you be using?" he says. "Don't tell me 134a"!

"I am thinkng about Freze 12. Ever hear of it?" says I.

He then proceeds to tell me about R414, which he recommends, or R419 which he says is "like R12"

"Freeze 12 probably has benzene in it and you can overcharge and cause an explosive situation."

Then he hands me a sticker for his favored R414 and it reads "Hot Shot"

Now, I don't know what to use, but will probably go with the Freeze 12, because many here are having success.

Any comments?

I tried one of those on my '84 last year before I converted it over to 134.
It froze me out of the car.........for about 3 days before it all seeped out of the hoses.
I then sucked it back down and filled with 134, not as cold, but no problems.

Your refrigeration guy is a moron. Freeze-12 does not contain any hydrocarbons and is not explosive. On the other hand, HotShot contains isobutane, which is explosive. The small amount of isobutane, in my opinion, doesn't justify worrying about it but it exists none the less. I'm not sure what you are doing, but if I were putting together a new A/C system from scratch, I would use 134a (like every new auto A/C system manufactured today... how can all the car manufacturers be wrong)? If I were trying to reuse some or all of my r-12 components, I would use freeze-12.

In my girlfriend's '89 740 it has a new condensor, receiver, and compressor with r-134a for 2 years now and still works great, vent temp in the mid 40's on a 90+ degree day.

In my '89 740 I used all the original r-12 parts and recharged with freeze-12 and it is working great, vent temp in the low 40's on a 90+ degree day. I can't comment on longevity yet since I did this only 3 months ago.

--
Matt L. -- Cary, NC -- '89 740 sedan -- '91 740 wagon

hi, got a question.....
my brick ('91 940 gle 16v, 115k) still have the original r-12 and i recharged a can of r-12 last year, works great but i noticed the ac is "less cooler" this year, anyway, can i recharge with freeze-12 to the system while still have r-12 in it, tia for any comments. happy july 4th......

According to the U.S. EPA, Hot Shot is:

50% R22
39% R124
9.5% R142b
1.5% isobutane

R22 needs barrier hoses, pure and simple. The refrigerant might otherwise fractionate and leak out the R22, leaving the remaining refrigerants behind. I'm sure they say it doesn't fractionate, but I think most of the R22 blends eventually fizz through the hoses. McKool certainly does, at 55% R22.

Freeze 12 is 80% R134a and 20% R142b.

--
1992 940 wagon, 72k