MILKSHAKE - water in engine oil, where to start?

[tcgravy]

Pulled the dipstick yesterday and got milky oil.

Engine oil was changed at the beginning of season, boat has been ran 4 times since then without any problems.

Engine has been running just fine, absolutely no problems and wouldnt have noticed anything without checking the dipstick. It was ran on a hose /muffs before last outing and the muffs fell off, had to replace impeller - don't think it overheated, wasnt that long and only at idle, but not sure.

1987 5.7 350 mercruiser, 4 barrel carb, engine was rebuilt 2 yrs ago by previous owner. thru prop exhaust.

My question is where to start....I've done some reading and am looking at exhaust gaskets being the first place to check, then head gasket, also intake. Have never worked on boat engines before, but I'm ready to get this thing back in the water.

Thanks for the help in advance.

 

[Bondo]

Re: MILKSHAKE - water in engine oil, where to start?

Engine was changed at the beginning of season,

Ayuh,....

New or Used,..?? How much of it,..??

 

[Squid Billy]

Re: MILKSHAKE - water in engine oil, where to start?

Head Gasket, Oil does not go to the manifolds.

 

[daringmor]

Re: MILKSHAKE - water in engine oil, where to start?

I have the same problem. I took my boat (1986 Bayliner Capri) to the shop to give it a tune up and put a new water pump on it and while it was running they said the engine started to miss. The mechanic told me there was water in the oil.

Is it the head gasket? Or could it be the intake or even a cracked block?

Thanks!

 

[Squid Billy]

Re: MILKSHAKE - water in engine oil, where to start?

Oil does not pass through the intake and it is possible it is a cracked block, but 9 out of 10 times, it is a head gasket. if caught early enough, it can be fixed with just a new head gasket. A motor still can run ok with milk-shaked oil as long as it has not been pushed very hard, after all water will cool and act as a lubricant, just not that well when under hard forces in a engine.

On a V 6-8 engine a intake could be cracked to leak water into the crankcase from above but it's not to common. More than likely it is a section of the head gasket that separates the oil passage from the water passage that has failed. Most times if the motor seems to run fine but their is water in the oil, you did not ruin the motor. If its running real ruff, well then you could have cracked the head.

 

[ziggy]

Re: MILKSHAKE - water in engine oil, where to start?

water in engine oil, where to start?

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

http://www.boatfix.com/merc/Bullet/01/01_10.pdf

 

[bruceb58]

Re: MILKSHAKE - water in engine oil, where to start?

Head Gasket, Oil does not go to the manifolds.

It could be bad manifolds and/or risers. If the oil is just milky and there isn't much rise in the oil level, it can easily be that. When was the last time you changed the manifolds? Do you boat in salt water?

Was the boat winterized properly? Does it get below freezing where you live? Could also be a cracked block for these instances.

 

[thundercat 9]

Re: MILKSHAKE - water in engine oil, where to start?

I had the same symptom, ended up being a head gasket/head problem. My motor runs in salt water and when I pulled the head off, one of the water jacket holes was rusted so bad that the area between it and the combustion chamber was almost non existent. I would do a compression test.

Good Luck

 

[Squid Billy]

Re: MILKSHAKE - water in engine oil, where to start?

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

http://www.boatfix.com/merc/Bullet/01/01_10.pdf

ziggy,

Very good links!

Bill

 

[tcgravy]

Re: MILKSHAKE - water in engine oil, where to start?

Going to check compression and try and pressure test manifolds/risers today.

Part of problem is that I bought this boat about a month ago, so don't have a lot of history with it. I was told by previous owner that oil was changed at the start of this season (right before I bought it) and everything was fine.

Will get back with more info on compression and the pressure test on the exhaust.

Thanks for the help so far........

 

[thedillybar]

Re: MILKSHAKE - water in engine oil, where to start?

I have an idea (haven't tried it) rather than removing exhaust manifolds/risers and pressure testing them.

(One side at a time)
Plumb the garden hose to the exhaust manifold (where raw water enters from T-stat housing). Turn the garden hose on w/o starting engine for 5-10 minutes.

Look through spark plug hole for water entering cylinders while hose is on.

Shut off hose. Check dipstick.

If you see water entering cylinders while hose is on, or you see a higher fluid level on the dipstick (with more water) then the manifold or riser or elbow is bad.

Not worth replacing individual parts if the damage is from normal, long-term wear & tear...replace manifold/riser/elbow on both sides.

 

[Squid Billy]

Re: MILKSHAKE - water in engine oil, where to start?

Well like the links say, ... Run the motor up to operating tempature to do your test.

Reason;

The the motor expands with heat and vibration, cracks get enlarged, hot water and steam will find their way through them better than cold water the hose.

just my 2 cents worth!

 

[thedillybar]

Re: MILKSHAKE - water in engine oil, where to start?

I do like that theory...but then I can't eliminate the cause being a leaky intake manifold gasket, head gasket, or cracked intake manifold, cracked head, cracked block.

I guess I could warm it up and check the oil. Then use the garden hose with the manifolds still hot.

 

[imported_TheMan]

Re: MILKSHAKE - water in engine oil, where to start?

Deleted

 

[Squid Billy]

Re: MILKSHAKE - water in engine oil, where to start?

Then use the garden hose with the manifolds still hot.

NOOOOOOOOOOooooooooooooo!

Hot Part, Cold Water, you might as well hit them with a sledge hammer and buy new ones!

 

[thedillybar]

Re: MILKSHAKE - water in engine oil, where to start?

Go to the lake, run the engine up to operating temp.

Now that impeller is pumping that cold lake water through the t-stat housing and into the "hot" exhaust manifold. Let me know how that works out for you....

What difference does it make whether the impeller pumps it through the t-stat housing, or the garden hose pumps it directly into the manifold?

 

[bruceb58]

Re: MILKSHAKE - water in engine oil, where to start?

I would do the pressure check on the coolant system and also do a cylinder leak down test. I would also pull the risers to see what the riser.manifold connection looks like.

What is the oil level at?

 

[tcgravy]

Re: MILKSHAKE - water in engine oil, where to start?

Oil level is 3 inches above full.

 

[bruceb58]

Re: MILKSHAKE - water in engine oil, where to start?

Then its not going to be the manifolds. You are looking at a crack in the block or a head gasket. Time to do a pressure test.

 

[thedillybar]

Re: MILKSHAKE - water in engine oil, where to start?

3 inches above full is too much to be an exhaust manifold or intake manifold gasket? That'd be what, 3 or 4 quarts of water?

Even if it's been out a few times since the oil has been checked?