Does anyone out here believe in the old-school radiator plugging technique of dumping pepper (as in salt & pepper) directly into the rad?
When I was offroading in the 80s, I came around a turn I was used to but there was a freshly fallen branch where it shouldn't be, which jabbed right through the middle of my car's rad. It severed 3 of the lines. My father in law looked at the damage, crimped the busted lines with a pair of needlenoses as best as he could, dumped a shaker of pepper in the rad, topped-off with water and told me to start driving. The pepper would somehow react wherever there was any leak and permanently seal those leaks.
I ran that car for several more years with no cooling issues. No one I've ever mentioned this to has ever heard of doing this. One more try!
EDIT: now that I google it, there are lots of references click