Thanks everyone for your sage advice.

The common consensus is to replace the radiator with a new one. I'm trying to
source one locally (Canada) but if I don't succeed I'll order one from The Bus
Depot. The problem is the cross border shipping constipation in the wake of the
WTC/anthrax/whatnext threats. It may be better to just drive down and install it
in the Good Ole U.S. of A. :-)

Thanks again,
Larry