1993 Nissan Truck raidiator fluid leak & over heating

My 93 nissan truck with the KA24E engine did the same thing. The problem was the timming chain guard inside the housing had completely worn out and the pieces are in the bottom of my oil pan. When the guard wears out the chain did flex to where it cut a hole in the housing. The water jacket is right where the hole was. I put stop leak in it and slowed it down but the chain kept wearing a bigger hole. The water in my case showed up in the oil. I tore it down and had the chain guard replaced( nissan made the new one better so they do know they have a problem) and had the housing hole welded. It did fine till the transmisson bearing went out. That cost $950.00. Now a have a Rpm problem that I have posted but no responses. Good Luck