R12 is a "banned" substance now. I.E. you are supposed to stop using it
(older cars using it are grandfathered, but new cars can't use it.)

R134a is the replacement for R12. Different formula of gases. Not as
effective in cooling, but if different evaporators are used, it can
still be pretty effective.

Freeze 12, Duracool and other similar products are yet another
formulation of gases. Mostly based around propane and butane. However,
don't make the mistake that these are less or more flammable than other
freons. Given sufficient opportunity any of them can be made to burn.

I've got Duracool in my GoldBrick. Works quite nicely. The major issues
are, that you must be careful to not let it get mixed with 134a (i.e.
if another shop services your vehicle they must know about it.) This is
 >NOT< due to the flammability issue, but rather due to the PRESSURE
issue. Duracool and Freeze 12 can create much HIGHER pressures than
134a, and those higher pressures can damage equipment used for
recharging systems.

Duracool or Freeze 12 having cooling properties similar to the original
R12 used in your Vanagon, and hence I feel are better choices. However,
few US shops use Duracool or Freeze 12 themselves (though it is legal
in many jurisdictions.) It is legal for use in Europe and Mexico I
believe.

On Wednesday, May 14, 2003, at 11:27  AM, John Rodgers wrote:

> What are the
> differences between R12, Freeze 12, and the 134a??