Hydro lock on cold start 350 V8

griff4

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Joined
Dec 31, 2013
RO Number
33534
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34
My 2007 Bayliner 325 has a pair of 250hp 350 engines. Lately, it has shown a hydro lock during cold start attempts. A small amount of seawater is in no. 1 cylinder only. I suspected exhaust manifolds and risers. Changed them and the condition still exists. Has anyone had this condition before? As always, suggestions are welcome. Griff
 
I had a similar situation years ago on my 454CI engine. It was caused by an internal crack in the manifold between the water jacket and the exhaust channel.
 
quote:

Originally posted by pdecat

Check compression on that cylinder






x 2 .

And check oil for water contamination too.

Head gasket or crack?

This engine is RW cooled , right?
 
Yes, raw water coooled. General consensus seems to suggest a possible headgasket failure. I will check a few more things before tearing the cylinder head off. Thanks all for your expert advice. Griff.
 
At 13 years old it could be a headgasket or a crack in the head or a corroded hole at /under the exaust valve
 
All apart now. What a mess! Looks like the intake manifold gasket leaked seawater into the no. 1 cylinder intake port on the head. Lots of rusty stains coming down into the no.1 intake port. Head gasket may be not the problem. But gotta clean up this mess and reassemble all very carefully. Thanks to all for your thoughts and expert advice. I will report upon completion. Griff.
 
All back together now. Purrs like a kitten. Problem was an intake manifold gasket. Thanks so much for your advice. Griff
 
Those gaskets can be a problem, good thing you caught it before it did too much damage.
 
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