50 years ago when roads were rough and trucks vibrated a lot we were constantly plagued with leaks. Bars with the standard fix and we never ruined anything. Back in those days the stuff came in glass bottles and we always carried a couple of bottles. Later on we started carrying Alumaseal. Both products worked well and I wouldn't be afraid to use them today. Since we went to all aluminum radiators on our trucks we just don't have leaks. Occasionally a heater core will leak. We turn off the water filter, put in a couple of doses of Alumaseal and go until we have time to replace the heater core.