I may try this, but it’s only rated to 250F. The temperature of my coolant is normally 190F, so that doesn’t leave a lot of room for error…
http://www.devcon.com/devconfamilyproduct.cfm?familyid=310&catid=26
I may try a JB Weld Product. Good to 500*F. I’m torn between Waterweld, Marineweld, or just good old fashioned JBWeld…
http://jbweld.net/products/index.php