The hydrolock drama continues.

My insurance company seems to have determined that the cause of the failure was
the aftercooler. Their surveyor pulled the zinc plug on the aftercooler and
found an "inadequate" amount of zinc on the plug. (It was ready to be changed).
The surveyor immediately concluded that the aftercooler had not been properly
maintained with zincs over the years.

TADA! For some weird reason I've been keeping the used up zinc stubs. I have
several of them on a shelf in the engine room. Among the stubs are several of a
diameter that doesn't fit *anything* except the fitting on the aftercooler. If
it turns out that I'll need to prove that I've been changing the zincs in the
aftercooler, I will have some means to do so........(or else I've been
scrounging around for used up zinc stubs) :-)

What a hassle.