Hydro locked Merc 4.3 - can't stop the water

[boatrboy]

Helping my friend and am stumped.
2005 4.3 Carb. New dry joint last year - real Merc parts.

Motor hydro locked so I pulled plugs and port side seemed to have wet plugs but cylinder in front had a lot of water. After cranking in spurts, the front cylinder never stopped spitting water out. When it seem to get better we started motor and seemed to run ok. I pulled those plugs again and there was water again in front and never seems to dry out.
Compression on middle and rear was 180 but front still had water while I tested it and it read 210 +.

We drained block (port side only) and exhaust water and removed belt so water would not be circulating but the water never seemed to clear out while cranking.

My friend insisted intake manifold - we pulled it and I don't see a smoking gun. I pulled exhaust and see no signs of rust. I did see what appeared to be water in the top of the elbow but the components had black carbon not rust so it's possible when I laid them down I got water in them.

I am at a loss and want to change head gasket since we almost there but my friend talked to a supposed Merc expert and wants to put everything back together and pressure check water passages insisting this should have been first step to check for cracked block or head.

I can't image a cracked block would not have been noticed in the ten or so hours he has run this year so far.

Any ideas?

Thanks - Mark

 

[scoflaw]

Agree, pressure check the water side of the motor

 

[boatrboy]

Agree, pressure check the water side of the motor

Please elaborate - if we pressure test by blocking off water lines going into exhaust , the pressurize the thermostat housing, won’t water enter cylinder if a head gasket is blow as well as if the block is cracked?
I am not sure of the pressure test procedure and what it will tell me.

Thanks

 

[scoflaw]

Please elaborate - if we pressure test by blocking off water lines going into exhaust , the pressurize the thermostat housing, won’t water enter cylinder if a head gasket is blow as well as if the block is cracked?
I am not sure of the pressure test procedure and what it will tell me.

Thanks

Well since you already have it torn down to that point, you might as well pull the heads and have a look. Blocks tend to crack in the lifter valley, should be visible with the intake off.