I have seen this a few times before.  It seems like cylinder #3 on the
watercooled is the first to fail when the engine overheats.  You wouldn't
think this to be the case as all three cylinders should be equally cooled by
the coolant right?  Yet I had one motor with the exact same melt down
scenerio as John's and another with a dropped valve seat on number three
(that was due to the failure of the coolant fan).
Any ideas as to why #3 wants to croak first on the waterboxer?  I have been
told that the aircooleds have this problem because the least air gets to that
cylinder but apparantly the watercooled engine still has a "ghost" of this
problem as well.

Also any hypothesis about what actually caused John's cylinder to fail?  I
had alot of them with the customer's engine that had a similar meltdown.
Never really had any solid answer though.  I felt it was due to detonation
because the piston tops were quite carbony.  The fuel injection system was
going haywire because of a missing engine ground strap (left off by the mechs
that installed the VW Dealer Rebuilt engine).  Couldn't ever prove this
though.

Finally, John, although I am happy your three pistons and cylinders are still
good, unless you can find someone to sell you just one P and C you are out of
luck.  These are only sold in sets as far as I know of.  Are there three
other folks out there who need just one piston and cylinder?

Ken Wilford
http://www.vanagain.com
John 3:16
Office (856)-765-1583
Shop (856)-327-0027
Fax   (856)-327-2242