My F-350 sprung a tiny leak (pinhole near the upper hose snout) the day before we left for WV (Chaos Offroad Park) last month... scuffed it with dragons tongue, sprayed it with brake cleaner, squirted a blob of JB Weld 5 minute and let it sit overnight.
Held fine dragging the Moss (about 8k# total) at 80MPH on I-81 and much slower on the narrow/twisty roads approaching Capon Bridge. Still holding good so far, but a new radiator is in it's near future!