There are three basic ways water can be leaking into the "oil bilge" area.
1. The engine has a water leak somewhere in its cooling
system, and the water is dripping into the oil bilge
. If this is the case, careful observation will find it.
2. The saildrive
leg sticks down thru the engine bed
and out the bottom of the hull
, and the area surrounding the leg inside the hull
is filled with water. This area is sealed from the interior
of the hull with a heavy diaphragm
which is clamped down onto the engine bed
with a metal clamp ring. If the hold down action of the ring has failed, or the diaphragm
has started to leak, water can leak in and run into the bilge. Again this should be visible by careful examination around the seal, particularly in the area of the flywheel housing.
3. When the engine bed is shaped and glassed to the hull, the bed is glassed to the hull around the exterior perimeter of the bed, around the interior
perimeter of the oil bilge, and around the interior perimeter
of the cylinder thru which the saildrive
leg protrudes. If a crack or de-lamination of the glass around the cylinder occurs, this will allow water to enter into the area below the bed, and this water might be working its way into the oil bilge.
My feeling is that the order of probability of one of these problems occurring is highest for #1, and lowest for #3. But, never say never.....
Attached are a couple of pages from a Volvo installation
manual which might make my description of the glass work more understandable.