Still trying to diagnose cracked block

[xadiohead]

Back in April I created a thread regarding water in my oil (link is below)
I know creating another thread is not advised but it has been 5 months and that thread went over 5 pages and I didn't want people to have to read through a lot of irrelevant information. I ended up buying another boat to use for the summer which I recently wrecked towing. I now want to go back and finish trying to diagnose this boat.

Basic recap:
1) Last fall I thought I winterized boat correctly. (I pulled all five plugs, briefly cranked engine a couple times, and even poured antifreeze down most of the hoses including the exhaust manifolds. Only place I naively didn't put antifreeze was into intake manifold) I also changed oil which looked very good.
2) In April went to start boat on muffs and it kept hydrolocking after sitting overnight. I would have to pull plugs to clean cylinders out each time.
3) Did compression test and the numbers seemed pretty normal (within 10%)
4) Replaced exhaust manifolds which fixed hydrolocking. I had the original one piece manifolds which were 15 years old.
5) Thought I was good but then checked oil after running a day and the oil was greenish.
6) Changed oil and filters a few times and still INSTANTLY turned greenish on muffs.
7) Tried to do pressure test but couldn't ever figure out how to get connections correct. This is where I gave up in May and bought another boat.
8) Also never did leak test as I don't understand how to do account for TDC
9) Yesterday pulled the intake manifolds and had the milkshake underneath. Here are pictures: https://www.dropbox.com/sh/ie6s51h7s...IR-vRL6Ya?dl=0
This is the first time I saw this milkshake as my oil was greenish liquid, not this milkshake. I was told these blocks are notorious for cracking in the valley. I cleaned the mess up as best as a could and didn't see any cracks. I'm not exactly sure where the "valley" is people talk of or if it is just everything under the intake.

Should I just consider this block garbage even though I have seen no physical evidence of a crack? The boat did overheat (steam came up from engine) in May 2013. I never saw any affects from the overheating but i'm sure it had some (weakend head gasket?)

Is figuring out how to do the pressure test still my best bet? I guess I am still hopeful it might be a bad head gasket since I have seen no signs of a cracked block and I drained the water, though I do realize they are internal many times.

Thanks

 

[xadiohead]

Here is the original thread:

 

[alldodge]

The greenish stuff at the muffs would tell me your outdrive lube is getting mixed. Mercruiser lube is green in color. Edit: Now if this is closed cooling then that is antifreeze leaking, and when mixed with oil will still turn white. As for the milkshake, I would say your intake is leaking water into the valley pan. Looking at your intake ports they are all rusty. My suggestion would be to pull the engine, strip it down and send it to a machine shop for cleaning and pressure testing

 

[Bondo]

The greenish stuff at the muffs would tell me your outdrive lube is getting mixed. Mercruiser lube is green in color. Edit: Now if this is closed cooling then that is antifreeze leaking, and when mixed with oil will still turn white. As for the milkshake, I would say your intake is leaking water into the valley pan. Looking at your intake ports they are all rusty. My suggestion would be to pull the engine, strip it down and send it to a machine shop for cleaning and pressure testing

Ayuh,..... I completely Agree,.... By pullin' the intake, you've got past backyard pressure testin' at this point,....
By yer description of how ya got here, it might be salvageable,.....

 

[xadiohead]

The greenish stuff at the muffs would tell me your outdrive lube is getting mixed. Mercruiser lube is green in color. Edit: Now if this is closed cooling then that is antifreeze leaking, and when mixed with oil will still turn white. As for the milkshake, I would say your intake is leaking water into the valley pan. Looking at your intake ports they are all rusty. My suggestion would be to pull the engine, strip it down and send it to a machine shop for cleaning and pressure testing

Sorry I may have said that incorrectly. Just to clarify, the "greenish oil" was the ENGINE oil and happened multiple times even after changing the oil and filter. I was just testing the engine while hooked up to the muffs but nothing was coming out the muffs or anything like that. The outdrive appears to be perfectly fine. I have a freshwater cooled engine. Is it even possible for outdrive oil to make its way into an engine?

 

[alldodge]

You need to tear it down

 

[xadiohead]

You need to tear it down

Unfortunately I don't know how to tear an engine down. Yesterday was the first time I have ever even removed and intake manifold. Is this something I could have a regular car mechanic do?