Ran the engines(Crusader 7.4 mpi)at the dock the other day and after a few minutes the coolant expansion tank was overflowing. No overheat. Today I added water/anti-freeze to the engine and took it for a test run. Hatch was up for 15 minutes to see if problem repeated. Nothing happened. Shut the hatch and when I got back to the dock the expansion tank had overflowed and water was everywhere. No overheat. Any suggestions are greatly appreciated.
Hank
Hank