> Aside from the corrugated bit I like your theory.

I just checked mine again and sure 'nuff, like yours, it's NOT
corrugated. There's a pattern of rust on it that gives it the
APPEARANCE of an uneven surface. I clearly didn't look very closely
before I tossed it into my toolbox, cursing VW engineers righteously
as a lay on a piece of cardboard under my van at a gas station off
US-101 on Malibu Canyon Road....

Looking at that, I feel I must amend my theory slightly. I suspect
that it's not just cooling system pressure, but also that the clamp is
squeezing the soft tube, pushing the steel insert out, like toothpaste
out of a tube. That fits better with the nature of the GoWesty fix, I
think.

--
John Bange
'90 Vanagon - "Lastwagen"
'90 Vanagon GL - "Wiesel"