I have a 2001 F250 4x4 with the V10, its my wifes truck she said she keeps having to add water. here is what its doing, when running for minutes or a hour it doesnt leak water from the radiator until the engine is shut off. and then it only drips about a quart or so. and it doesnt do it all the time maybe every 4th or 5th time she uses it. I ran some Bar's heavy duty seal through it and it still hasnt sealed 100% now its only dripping about a pint but it just will not stop it completely. besides replacing the radiator what else can I try.

 

Just replace the radiator.