4.3l Mercruiser water in oil but not in cylinders

sherbert1060

Recruit
Joined
Jul 5, 2011
Messages
1
Hello All,
My uncle has a 2000 Ebbtide with a 4.3l v6 in it and mercruiser alpha mr1 sterndrive on it. He lives in the south east, and he drained all the water out using all 5 drain plugs, the fogged it and left it for the winter. He suspects he might have frozen the block by not getting all of the water out but I dont think so. It doesnt get cold enough and theres no way enough water was left in there to freeze it.

Anyway, he checked the oil (looked fine) then fired it up this summer and it started great. Took it around the corner on the lake and hit WOT for a minute or two, then started to slow back down and noticed the motor was lagging and not running right. He checked the oil and it was full of water. He brought it back to the house, and took off the PCV valve and water shot out like a fountain. But the motor still runs. He is doing a compression check for me but it isnt hydrolocked at all.

We are trying to determine if it is a head gasket or cracked block. If anyone has had a problem like this please let me know, will be glad to provide any other necessary information.
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,111
Re: 4.3l Mercruiser water in oil but not in cylinders

remove the thermostat housing and see if there is a hole thru the manifold.
 
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