Freeze-12 is 80% R134a and 20% some other refrigerant that doesn't come to
mind at the moment- the '20% other' is supposed to reduce operating
pressures to within R-12 spec so as not to overload the equipment.
I read a description of the result of mixing R-12 and R-134 and their oils
as being something akin to wet yellow popcorn. Not good.

Here's this in case you don't have it:

http://www.gti16v.com/tb879503.htm

That should get you started.

Cya,
Robert

----- Original Message -----
From: "Kim Brennan" <kimbrennan@MAC.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Tuesday, May 30, 2006 1:36 PM
Subject: Re: AC tinkering

> You should not mix refrigerants. That's not just a recommendation,
> its EPA rules.
>
> Freeze-12 is (I believe) a mix of R134a and other refrigerants, but
> even so, you should never mix refrigerants on your own. Either get
> your system recharged with R12, or get your system converted. If you
> aren't going to stay with R12, you should get your system properly
> converted to R134 (change of oil, receiver/dryer and new quick
> disconnect fittings).
>
>
> On May 30, 2006, at 2:39 PM, Susan Powell wrote:
>
> Got a '87 with a "sorta" working ac.  I got some Freeze -12 but
> wondering if it will mix with whatever old R12 is in the system or
> should I evacuate the system and start from scratch?  I would like to
> just get something in it to help with cooling car but I don't want to
> wreck anything.  I have learned alot about vanagons from this forum.
> Thanks for the comments.  R, Steve