[Shabah z252]

I’m looking for a little input, Engine is 5.7lx throttle body injection with bravo 3.
The other day I blew the porcelain out of a plug while running wide open. Got towed in and had a little water dripping from the exhaust manifold. I bought new plugs and when I took out the old threaded part there was some water in the cylinder. I put the plug in thinking it was residual and about 10 minutes later remembered I forgot to gap it. When I took the new plug out, water drained out of the cylinder like I was draining the block. I thought maybe my exhaust manifold gasket blew out or the manifold and elbow failed. So today I changed the manifold and elbow and cranked it over without a plug. Unfortunately, water still shoots out even before the sea water pump pumps water to the elbow on the exhaust manifold. (The cooling line from the thermostat housing to the exhaust manifold is dry)
So I’m wondering if anyone has seen this before? Is there any chance that it’s the intake manifold gasket? Or is it more likely a head gasket?
The boat didn’t overheat and has been running great up until this point.
I just don’t understand how something so catastrophic can happen without warning.
Sorry for the book but any and all help would be greatly appreciated

[Hudson River Steve]

Sorry to say but it sounds like a head gasket or maybe even a cracked block. In any case a tear down is in order so you can inspect/find your water leak.

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[Shabah z252]

Thanks for the reply,
I was afraid of that. Wouldn’t a cracked block have made itself appear before all this? The boat was winterized and stored inside heated. If I pull the intake manifold would I be able to see cracks possibly? I’ll do some investigation before I call the marina that winterized and stored it. Thanks

[Hudson River Steve]

Impossible to say exactly what is wrong. Could be many things: Crack in exhaust manifold that let water in, intake or intake gasket, head or head gasket, block. If it blew the porcelain out of your spark plug you may have had water enter the cylinder while it was running. Water does not compress so the pressure may have been high enough to blow out the porcelain. It may have done other damage as well such as bent a rod or spun a bearing. Time to tear into it and examine everything. Sorry.


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[Shabah z252]

Thanks for the input. Gonna have to start digging