I had excellent luck patching my coolant overflow tank with Permatex Black
Super Weather Strip Adhesive #82.  I applied a thin coat to the crack,
then cut a patch out of a mylar party balloon.  I then sealed the patch
with another coat of adhesive.  It lasted for two years, when I finally
got around to putting in the new tank.  This setup lets the tank expand
and contract without breaking an epoxy patch.  I also use this adhesive
for water pumps.  I got the tip from a long time mechanic. Cheap with many
uses.

Bill

----- Original Message -----
From: "Doug Alcock" <dgalcock@HEWITT.COM>
Hi Dar,

     I fixed the main water tank in my Westy with epoxy putty. 'twas a
rather
nasty crack around the joint where the outflow joins the main tank ---
sounds
sort of like
your problem. I just packed the crack and smoothed a layer on top of that.
It
was almost
perfect after one application ---- duct tape made it perfect. Probably
worth the
$6 or so
for a pack of putty ---- I *know* you already have duct tape. Besides, the
duct
tape will be an
aesthetic match to the 'gray' water tank :-)

Hope this helps,
Cheers,
Doug
'84 Westy
Toronto, Canada