One other tip that I'll include that's more than obvious; if you're going to change out a radiator (or any other similar hose) you can often save some grief by cutting a long slit in the hose lengthwise on the fitting and give it a gentle twist. That will usually break the seal that forms on the outlet. Slobber a little bit of whatever the hose carries (in this case antifreeze mixture) on the inside of the hose before you slip it in place...slick!