A friend just replaced an exhaust manifold with the same problem.

Mick


"bob" wrote in message
...
How do you trouble shoot the cause? Intake gasket vs head gasket vs crack
somewhere? Done some searching in this group and hoping exhaust manifold
may
be the problem but don't want to tear it apart if I can do some
diagnostics
first.

I posted this last summer but problem appears to be back. This is a
Mercrusiser (Chevy 350 block in a 1992 boat) that I overheated due to raw
water

pump failing (now have a buzzer installed). On this occasion, I launched
and
drove slow for 1/2 mile or so and then pulled a skier 1 mile or so
(3200rpm or
so) and noticed temp gauge pegged so stopped.

At that time,I pulled heads, all pistons pretty much the same black top,
had
heads
milled and valve job (motor has ~1200 hours on it). Cleaned block and
intake
and put back together. Not sure I wasn't still getting some water in oil
after

this as I could see some condensation under oil filler cap and either lots
of
blow by or steam coming out of the valve cover vents but it seemed to get
better as the motor warmed up. Assumed it was condensation. Changed oil
today
and
looks like chocolate milk...

Without any good diagnostic test I guess I will just start to pull apart
and
see if I can find anything. Tried to do this last year but the gaskets
tear
and can't really tell if it was leaking or not. I'd love to just change
the
exhaust manifold or intake gaskets if that is all that is wrong but if I
have
to tear down to the heads again, I will probably just go for a complete
rebuilld and have
everything checked. I really don't think it needs it as there was no
ridge
ring that I could see or feel.

Thanks for any and all advice.
Bobby