I have a 454 volvo penta in a 1991 cruiser with closed cooling. the problem started with a leak at the end cap of the heat exchanger above 3000 RPM. "this ruined the alternator on the port engine" I finally got that leak stopped after using 3M 5200. then it started leaking at the seam between the exhaust manifold and the riser. it appears that there is abnormally high pressure in the saltwater side of the cooling system but an engine rebuilder said that was not possible, and I just had a combination of bad gaskets. he suggested I take it apart and grind the two surfaces flat and replace the gasket. the boat is in the Keys and I can;t find anyone that works on V8s down here. HELP