I have a bukh dv10 in my sailboat, and recently had water in the crankcase due to corroded water pump housing bearings. I also had a problem with the thermostat housing, and had to take off the head in order to get at it properly.
On removing the head, I noticed that there are two holes in the head that match up with two holes on the top of the crankcase, leading to the water jacket. The head gasket also has holes in this spot.
The issue is that the two holes in the top of the crankcase are blocked, with what appears to be metal, as picking at it does not loosen it. The opposing two holes were blocked, but easy to dig out.
The question is, should I drill out the two blocked holes in the top of the crankcase?
I have a manual, but the exploded view of the crankcase does not show these two holes.
The water got in from the water pump, and I have ordered new bearings. The oil is now like mayonnaise, and I have managed to get most of it out from removing the head, the oil pan, and the front housing. I am also wondering if just replacing the oil and filter a few times will clean out the parts in the crankcase that I can't see.
Any suggestions appreciated.