CRYO-seal is another brand name of this stuff
<http://www.cryochem.com/dist.html>
<http://www.ssrintl.com/CRYOseal.html>. This stuff works by turning
to a solid only when it is exposed to moisture (such as in the
ambient air), at the leak point. Since moisture is what it works on,
your system must be evacuated (moisture remoded) before using it. It
shouldn't simply be added without evacuating the system.

CRYO-Chem, the manufacturer, states that it will not work for slow
leaks (must hold a vacuum for a couple of hours) and specifically
mentions that it will not work on moving parts leaks (ie, compressor
seals).

My understanding is that it is also not recommended if your leak is
in a hose, a condition which Vanagon/Westy owners are more likely to
experience than other car owners (we resist replacing those long,
spendy components).

Lots of people I've communicated with have had good experiences with
this product within the manufacturer's limits.

They provide a 1-year warranty on the work.

Dave

-=-=-=-

>It claims that this stuff quickly, permanently, seals leaks in;
>condensers,evaporators. accumulators,compressors,o-rings, gaskets, and
>metal, or rubber hoses.
>Seals multiple leaks, and circulates to prevent any future leaks.
--
Dave Carpenter

Whatever you wish for me,
May you have twice as much.