Hey Paul, yeah it's the tube going back to the reservior (header tank) The glue I used is a two part resin which I have used with great success on many applications over the years (dries hard like plastic), however, I bit the bullet and had the local Lincoln Mercury Dealer bring in new T-stat housing cover (PN RH-42) from out of province for the "Good Guy" price of $30 CAD + tax. I'll pop it on when I get a 180F T-stat from town.
Off topic, but did you have any luck with that E-Ram gadget? If so, does it work?
Thanks