I have read and read about the coolant corrosion problem and wanted to add
my thoughts since I not had heard this type of comment.

My feelings on the coolant issue are because of the propriatary nature of
the manufacturers formula, I bought the Autobahn stuff. I feel if I'm gonna
pay an extra $15, it is cheap insurance against a hedge in replacing heads
et al. Also I'm going with the distilled water too.

It seems that the corrosive nature of this system could use every possible
precaution.  On this feeling, I have a hunch,and it is without proof, that
the factory coolant may have a "sacrifical anode" ingredient. On salt water
marine engines which suffer the corrosive engine problem, a sacrifical
anode, usually a piece of zinc about 3lbs in weight is attatched to the
engine. I guess the metalugical deal is that since zinc's atomic number is
closer to lead, the base, the "corrosive" action prefers the zinc to the
alloys in the 2 stroke engine.

It would be a smart thing IMO to add this type of scarificial anode to the
VW coolant. I repeat that I do not know for sure they have it, everybody's
so cloak and dagger about what is in their stuff. But I'm going to go that
way. The "clue" for me was that the factory stuff has a "short" life,
replace every two years.  When manufactures are making long life coolant
why place the short limit? My guess is that since all sacrifical anodes by
design are depleted, that the 2 year life is to replinish the anode. I'll
post this mental meandering for others to comment and refine. I mentioned
this topic once and got no response.

I've heard on the list of several motors that used either distilled water
or the original stuff go well past the service life of non such systems.  I
realize that since water around the world varies greatly that it alone
could be variable in whether say an owner used Autobahn, and local water,
but still had a head leak.  Back to my original feeling. This system needs
every possible precaution done to help it.

Mark Keller
91 Carat WLE