Milky oil

[Pikey23]

Hi,
I have an 1984 4winns 195 Horizon Cuddy with a 3.0 mercruiser 140. I check the oil before we go out every time. I noticed today that it became milky. I am going to give you as much info as I can in an attempt to help solve my problem, so I apologize for the long winded post. I changed it at the start of the season and actually commented to my wife about how clean it still was last week. The temperature always stays around 140, but I noticed the other day that after shutting the motor off that it would slowly drift up to about 160. Which is odd for my boat. I did have a over rev for about 1 second ( about 5400 rpm) two days ago. We also worked the engine hard pulling two heavy tubers yesterday. The engine runs a little rough on a cold start, but smooths out and runs fine after warning up alittle. I have no oil leaks and my auto bilge pump has never turned on due to water in the bilge. What could I expect as a possible cause of the sudden water in the oil? Head damage? Head gasket? Could my short over rev have caused head damage? I plan on pulling the head tomorrow morning to replace the gasket. Should I look for anything else while I am there?

 

[Don S]

Re: Milky oil

How much water are we talking about? Thimble full or squirting out the top of the engine.
Here is a Merc service bulletin on water in the engine.

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

 

[Fordiesel69]

Re: Milky oil

No, dont; start there. Check the manifold and elbow.

 

[Pikey23]

Re: Milky oil

Don, Thank you for the link, I am talking about a small amount of water, The oil is just a little milky, it looked like brand new a few days ago, now it is slightly milky, most people would probably wait until it gets worse, I will not. Fordiesel69, Should I remove the manifold and elbow? What should I look for when I have them out? I am an automotive guy. That is why I went straight to a head issue. One more thing that I thought of, we tried a different size prop and pitch for a day, It was actually what the boat came with. I did notice some very strange noises coming from the stern when I had this prop on. They occurred just above idle. We spend alot of time in no wake zones. The day after we used the new prop is when I noticed the milky oil.

 

[Don S]

Re: Milky oil

There is a lot of testing you can do before you pull the head. Once you pull the head, you may not be able to see the problem, but can no longer do the tests.

 

[Pikey23]

Re: Milky oil

I will pull the plugs tomorrow and see what that tells me. Then I will run some of the tests described in the PDF link that you gave me. Any other suggestions of tests that I should run?

 

[Don S]

Re: Milky oil

Do a cylinder leakdown test, and pressure test the engine blocks cooling system.

 

[Pikey23]

Re: Milky oil

I pressure tested the block this morning. It held at 20 psi for more than an hour. I am attempting to locate a leak down tester today.

 

[Pikey23]

Re: Milky oil

I found a leak down tester! I will try it tomorrow. I drained the oil today and it smelled like gas big time. Almost like pure gas. I was wondering. If the diaphragm or a seal in the fuel pump went bad could it dump tons of fuel into the oil? Would enough fuel cause the oil to look milky? We have been using more fuel then normal lately. It is just a thought.

 

[Don S]

Re: Milky oil

Yes, the fuel pump diaphragm failure will fill the crankcase with gas, but gas will not make the oil milky, just thin. Milky means water.

 

[Pikey23]

Re: Milky oil

The test results are in. Now I need someone to tell me what they mean :redface:

Compression Test:
1) 130 psi
2) 135 psi
3) 135 psi
4) 140 psi



Leak Down results:
1) 10% air leaking out of carb
2) 10% air leaking out of carb
3) 8% air leaking out of carb
4) 10% air leaking out of carb



Thanks again for all your help Don

 

[Pikey23]

Re: Milky oil

So, I was not real confident in my leak down results. I had a friend stop by and help. Here the new results

1) 15% leakage Air leaking into valve cover
2) 20% leakage Air leaking into intake and valve cover
3) 25% leakage Air sounded like it was going into the oil pan. But, I could not feel anything from the dipstick tube.
4) 25% leakage Air sounded like it was going into the oil pan. But, I could not feel anything from the dipstick tube.

If #3 and #4 sound like they are leaking into the oil pan could this be a head gasket leaking with air leaking into the water jackets of the block? There was no cross over leakage between #3 and #4 cylinders. When I pulled the plugs all looked fine except #4, that one looked a little wet. Any ideas where to go from here? I would like to get this fixed right and get back on the water.

 

[Pikey23]

Re: Milky oil

any ideas? I could really use some help diagnosing this one! Any other tests I should try to run? Should I pull the elbow and manifold and inspect them? Do I just look for cracks and major corrosion of these components when removed? Thank you.

 

[Pikey23]

Re: Milky oil

I pulled the exhaust elbow and looked down into the manifold, it has water sitting in the bottom of it.
I took off the manifold and found some nice cracks on the intake side. Here are some pics-. Am i right to assume that this is my problem? Anyone know where to get a good price on one?

 

[Fordiesel69]

Re: Milky oil

This NOT good. This means:

1. When you pulled the elbow, the little bit left dumped down into the exhaust channel.
2. You have a cracked elbow somewhere.
3. You have a cracked or rotted out manifold (like I did).

You can invert the elbow on your workbench and pour a very light solvent like acetone, gasoline, laquer thinner, naptha, etc......... into the water channels. This solvent should not leak into the exhaust part of the elbow.

Same with the manifold log, rip it off, fill only the water passage with solvent and then watch for it to leak into the intake or exhaust channel. Do not waste time buying used manifolds. They will be equally as bad.....

 

[Fordiesel69]

Re: Milky oil

Yep, nice cracks!!!!!

Look that block over as well. Often people drain it, but not the manifold. Other times they drain nothing.

 

[Pikey23]

Re: Milky oil

Yep, nice cracks!!!!!

Look that block over as well. Often people drain it, but not the manifold. Other times they drain nothing.

I drained it. and then pumped about 15 gallons of RV antifreeze through it. This was before I got a heck of a deal on an heated indoor storage spot. So it was winterized and stored indoors. It ran all season with no issues until now. Should I change the head gasket while I am here? It is only a couple more bolts.

 

[Fordiesel69]

Re: Milky oil

You could, but make sure to use a good quality marine gasket. But in my opinion it never stops going just that tad extra. Pulling the head......then maybe do a 3 angle valve job while in there?

 

[Pikey23]

Re: Milky oil

I think that I will put it back together. I will pull the head in the fall and then look into a valve job.

 

[Pikey23]

Re: Milky oil

I would like to thank Don S and Fordiesel for all your help in solving my issue. I changed the manifold and ran it for 1.5 hours in my driveway, no water in the oil. I will take it out on the lake tomorrow and see what happens. Only problem I ran into was mounting the shift cable bracket. The new manifold had freeze plugs that got in the way. I found a new Barr manifold for under $250 at a local marine motor shop. Cheap and no shipping. They also sold me a carb mounting gasket for $2. My local marina wanted $28 for a carb rebuild kit just to get the gasket. Thanks again guys!