On a 2000 Mercruiser 5.7EFI with 335hrs that stopped dead at about 1000 rpm
with hydrolock after making oil from yet unknown location (flapper valve,
head gasket, intake gasket), what other damage or concerns should be looked
for (bearings, bent shafts, etc)? At this low rpm can we run 3-4 oil changes
through it, repair the leak and the engine be ok...or should we be looking
at a rebuild or remanufactured replacement.

Bad head gasket, cracked head?

I just discovered that I have the same problem with the same engine by
running an oil analysis. They discovered the byproducts of antifreeze in
the engine oil, so I caught it before it caused serious problems, I
think/hope.

Capt. jeff

Bad head gasket, cracked head?

or could be both.

glad you caught it. probably didn't do any other damage.but if the enging has
to be pulled for the upper-end repair. it doesn't take any extra time to pul
the pan and replace the rod & main bearings anyhow.

I'm hoping they can do it without pulling the engine. It's got 770 hours
on it and not due for this yet, I hope.

Capt. Jeff