Oily water!!

[cubester]

So, I bought a lemon. Mid 90's 140hp Mercruiser with Alpha Gen 2 drive. The impeller was incorrectly re-built, the previous guy wasn't paying attention and end of story. The entire motor/drive was rebuilt prior to the one boat ride where she overheated. Runs starts/runs beautfully until the cooling water is added. Intake is cracked, water is getting 'on top' of the pistons. Upon tear down the head has a visible crack between number 2 and 3.

Question is.... since the engine oil is milky (thus water contaminated) How could the water get down there? Is that a clear sign that the block too is damaged? Or, could water get around the rings and make that mess? Visually the cylinders appear to be crack free.... No i haven't magnafluxed it yet. What are the possible ways for water to contaminate the oil?

Thanks to all who reply,
Mike

 

[Don S]

Re: Oily water!!

If there is a lot of water getting into the oil, it's usually a sign of a cracked block (Freeze damage) since you already found the cracked manifold, you can bet the block is cracked too.

http://www.boatfix.com/merc/Bullet/01/01_13.pdf

 

[cubester]

Re: Oily water!!

The heads are water cooled. Depending on where the crack is, the water could easily be running back into the block.

The only way to know if the block is also cracked is to pressure test the water side.

Is there any way of doing that with the head off? The block doesn't have freeze damgae. Literally the boat had one run in water when she overheated after a full re-build. THere isn't alot of water in the oil....then again the cooling water experience is with the garden hose on the trailer.

Thanks