Water in Engine Oil

[potminer]

Here goes. Purchased a used '96 Bayliner with 3.0L Mercruiser this spring. Oil was clean/changed as I was told it was professionally winterized in the fall. I unscrewed all 3 drain plugs from the cooling system to empty any antifreeze. About a quarter cup of anifreeze came out from the drain plug on the block. That's it, no water. This is a good thing. So I don't expect a cracked block but you guys can be the judges of that. No visible cracks on the block to speak of. Anyway, I've had the boat out twice. Remember oil was ok before going out the first time. I didn't check the oil before second outting because first time out had been for less than an hour. Both outtings went well without a glitch. Engine ran great. I pulled the dip stick today and the color of the oil was like that of a cup of coffee with plenty of cream. Oil was up on dip stick only about 1/4" above the full line(may have caught it early or may be a slow leak). So I did a compression test on all 4 cylinders and all tested ok(145-150 psi). So I drained the oil and changed the filter. I also unscrewed the drain plug on the block for the cooling system(thought maybe some oil may come out of the block if it's cracked. Laugh if you want:redface:In case your wondering, no oil came from here. LOL).
So now I guess I should maybe pressure test the engine. I'm hoping it may be an intake gasket or at very worst a head gasket. Any marine mechanic is now booked solid til fall. If I want to do any boating this summer maybe I should just dump it and buy new. Any advise is good advise.

 

[Mikie Mikie]

Re: Water in Engine Oil

Can you afford 2 boats? Use 1 while the other is gone. I'm sorry, I had to put that out just because I have so many boats people laugh at me for it........Im not real familiar with the 3.0 Mercruiser but I have seen other engines that were equipt with an oil cooler leak inside the cooler. Any place water is right next to coolant separated by a thin piece of metal or an o-ring would be a chance for a leak, a rotted head gasket could do it I think, but if the leak was in the compression chamber of a cylinder it would probably leave evidence on the spark plug and I would expect it to progress into a knocking engine quickly, I wish I knew more about your particular engine.

 

[Fordiesel69]

Re: Water in Engine Oil

1.) Exhaust flapper missing.
2.) Riser elbow rotted or blown gasket
3.) Manifold has a pinhole or crack letting water into the exhaust port, then thru the piston rings. Etc.....
4.) Bad head or head gasket.

Drain the manifold and the elbow should drain too. Pull elbow, shine light down in manifold and look for water in exhaust ports. Also look at the flapper on the y-pipe while you are there.

 

[potminer]

Re: Water in Engine Oil

Where is the exhaust flapper located and how hard is it to fix if it's that or if it's an exhaust manifold? What elbow are you speaking of? Elbow directly connected to manifold?
Was the 3.0L mercruiser famous or known for such trouble?
Is the 3.0L mercrusier known for water in the oil for specific reasons?

 

[potminer]

Re: Water in Engine Oil

1.) Exhaust flapper missing.
2.) Riser elbow rotted or blown gasket
3.) Manifold has a pinhole or crack letting water into the exhaust port, then thru the piston rings. Etc.....
4.) Bad head or head gasket.

Drain the manifold and the elbow should drain too. Pull elbow, shine light down in manifold and look for water in exhaust ports. Also look at the flapper on the y-pipe while you are there.

So I drained manifold and removed the elbow. I shone light down in manifold and can't see any water in exhaust port. Do I have to remove the end cap of the manifold to see any water in exhaust ports? The y-pipe you speak of, is it the pipe which connects to the elbow? If so, I've found the exhaust flapper and although it is not missing, the one side of the flapper is not closed completely. Currently open about 1/4". Would this cause water to mix with engine oil? Thanks in advance.

 

[carcraze]

Re: Water in Engine Oil

I am not sure about the flappers, I do not have them myself but I understand they are there to stop water from entering the exhaust through a water surge from the Y pipe exhaust.

My advice is to pressure test what you can, make a block off plate for the elbow to manifold mount and seal the manifold. Pressure test the manifold and see if it leaks, there is also an acetone test you can do, best to do this off the engine. There is some info here on testing these. I would also do a block cooling water pressure test.

The elbows from what I know are difficult to test but if they are old and everything else tests fine may be time to change them.

If it turns out to be the motor leaking then you can start looking for head, gasket or block leaks.

 

[potminer]

Re: Water in Engine Oil

Upon further inspection I noticed water along side the exhaust port on the manifold. I'm talking about the small slots around the outside of the exhaust port. May not have drained the manifold initially(is there supposed to be a drain plug on the bottom rear of the manifold?). If so, it looks like the head of the plug is maybe sheared off. Anyway, yes there is water down along side the exhaust port. What does this tell me? Bad gasket between manifold and elbow? Bad exhaust flapper? Cracked manifold. Bad head gasket?

 

[potminer]

Re: Water in Engine Oil

Well I made my way down the y-pipe to the exhaust flapper. I think the flapper is fine. I get the idea that water will push up agaist the flapper which in turn closes off the exhaust port. Any ideas?

 

[potminer]

Re: Water in Engine Oil

Had mention in first post that I conducted a compression test and all was ok. Would this rule out the possibility of a blown head gasket or cracked head?

 

[dollarart]

Re: Water in Engine Oil

I had a 3.0 last year....water in the oil same as you. It was the riser....rusted inside and water was going back into the exhaust valve and into the piston and down to the oil.... I think !! Anyway, I changed the riser and all was good....no more water in the oil. I flushed 4 oil changes (including filters) quickly through it till then oil was clean. I used sea foam in each oil change to help absorb the water in tiny places. BUT....I lost compression in the rear cylinder and hardly any oil pressure. so I ran it on "3.5" cylinders for a couple of months very carefully till I found a new motor....... SO....better get on it quick....don't leave it sit.....and check the riser immediately.

 

[potminer]

Re: Water in Engine Oil

Thanks for the advice. Riser is rusted. Don't think that's the cause but no doubt it should be changed before it is. Can anyone confirm if manifold should have a drain plug on the bottom rear?

 

[potminer]

Re: Water in Engine Oil - Suceeded?

Re: Water in Engine Oil - Suceeded?

Well I changed out the manifold today and took ?r for a boot. All seemed ok. No water in oil and burned around the lake for about a half hour. Checked dip stick several times and no signs of water in the oil. Will let engine cool over night and check again in the morning but all looks well and hopefully stays well. Thanks to all for the advise.
One other thing happened on the water today. Was cruis'n at about 3/4 throttle when I thought I'd trim it up a little. Bumped the trim a couple times then lost indication on the speedometer and later realized that the "up" trim function no longer works. Still have "trailer" function so still ok but don't know what might have caused this. Don't know if speedo and "up" trim are related some how. Check fuses and all checked out fine. Any advise is appreciated.