Ray, I'm 100% with Dan. There once upon a time was a product that would stop radiator and heater core leaks pretty well...unless you had a system that required more pressure than about 9 or 10 pounds. In that case you had to leave your radiator cap un-sealed or it wouldn't work. It thankfully is gone now because as Dan said it would stop leaks and then later it would cause many more problems...some of which meant you would get the chance to have your radiator's core replaced because once it set it was in there until the cows came home. As for black pepper, theoretically it can work but anytime I've seen this done it was (a) a waste of black pepper (and only the Easter Bunny and the Tooth Fairy know how much to put in), (b) temporary...actually very temporary and (c) only worked on really tiny leaks---if it worked at all. The whole idea is it swells up when it gets wet and if it manages to find the pinhole leak as it is swelling up, it might stop it. Until you build up any pressure, that is.
However, you can use black pepper to stop bleeding. At least according to the Tooth Fairy and the Easter Bunny. And again nobody knows how much to use. Probably best to apply to steak, pork chops, hamburgers, etc.
