"Paul" wrote in message
.rogers.com...
The problem with pressure test is that it won't show the leak placement if
I'm correct. It would be a great after-repair confirmation that everything
is OK though, especially in comparison with the initial one. I have no
testing equip. and can't take the boat to the repair shop (boat is on
blocks
now). I've put the engine back together after replacing both head gaskets
and it failed the probe miserably so I have to revisit the issue again.



"Calif Bill" wrote in message
nk.net...

"rmcinnis" wrote in message
...

"Paul" wrote in message
. cable.rogers.com...
After taking the boat out just a few times this your I couldn't
crank
the
engine anymore. Replaced the starter, removed all spark plugs,
cranked
and
fount all cylinders in a 5L V8 OMC 305 engine flooded.

Does this mean that water came out of all 8 cylinders after yo had
removed
the plugs?

Since all 8 cyl. were
flooded at the same time with fresh water I do not suspect exhaust.
(verified by creating a closed loop coolant system and eliminating
exhaust
altogether).

I am not sure what you mean here. How does creating a closed loop
cooling
eliminate the exhaust? Did you create a closed loop cooling system,
run
the
motor and have all 8 cylinders fill with water again?

When you ran the motor this way, did you not have any water running
through
the exhaust system?

My suspect is a leak between cooling passages and cylinders intakes
in the intake manifold. Can't also imagine how a cracked block would
flood
all 8 cyl. at once.

If I understand the situation properly it doesn't sound like the water
enters the cylinder(s) while the engine is running, but rather after
the
engine is shut down. If you get water into one cylinder it is easy
for
it
to migrate to the other cylinders, all it takes is for the intake
valve
to
be open. The water will flow from the flooded cylinder up into the
intake
manifold. At least one other intake valve will be open at the same
time
which means it will flood also. When you crank the engine the
remaining
cylinders will draw in any water remaining in the intake manifold and
they
will flood as well.

You apparently have a leak between the water jacket and either a
cylinder
directly or into the intake manifold. This could be from a gasket
failure,
either the head gasket (fairly common failure) or the intake manifold
gasket
(pretty rare, but certainly possible). If the failure is in the head
gasket
a compression check should show which cylinder is the problem.

If the problem is not a gasket then I would bet that the intake
manifold
has
rusted through to the cooling system. If you still have your "closed
system" rigged up try pressurizing it and seeing if it holds pressure.
This
is a standard test on radiator systems, and you can purchase a small
pump
and pressure guage that installs in place of the radiator cap for this
purpose. The cooling system should be able to hold 13 PSI without any
significant loss.

Rod



Cheaper to take the boat to someone to do the pressure test. It is
about
$135 for the radiator pressure tester. They have been making these
things
for 50 years, and the price is still way to high.





Did you have the heads machined when replacing gaskets? Sometimes the angle
between the head and the intake changes enough that the intake does not seal
to the heads. Pull the intake and look at the gasket to see if it is
compressed all over. Auto parts stores do rent tools and you may be able to
rent a pressure checker.