Bad Exhaust Water Shutters - Water in Oil

[Driv3r47]

Went to change my oil after being out on the lake a few times and found the oil to be tan in color. Obviously water getting into the oil. Thinking worse case scenario... cracked block or bad head gasket. After doing a compression test I came up with 130-140 on each cylinder. No visible cracks in the block. Oil level was normal (not excessively high on the dipstick). Starts up easily, runs fine and doesn't overheat. Pulled the elbows from the exhaust system and found both exhaust water shutters missing (broke off and were sitting at the bottom of the exhaust).
Now that I've located the problem, I have replaced the shutters and have changed the oil twice after running for 10-15 minutes on the hose each time. Any way to fully clean out the residue from the oily water in the motor without changing the oil and filter 5 or 6 times? 1993 Mercruiser 5.7 V8/ Bravo I/O.

Thanks in advance!

 

[GA_Boater]

I don't think shutters will cause milky oil.

After running on the hose, is the oil level higher than when you started? Does the oil appear to be less milky?

I wouldn't change the filter every time. Cheap fresh oil will flush the filter and makes checking the oil level more accurate.

 

[tpenfield]

Agree ^^^ shutters won't be the cause of water in the oil. They do not form a water tight seal.

I would do a cooling system pressure test to rule out cracks or leaking in the cooling system.

 

[GA_Boater]

Skipped the pressure test. Brain isn't fully engaged yet. Thanks, Ted.

Another source for milkshakes is a cracked oil cooler if you have one.

 

[Driv3r47]

Thanks for the replies. No oil cooler. Kind of stumped at this point. I can pull the intake off and check the gasket after doing a couple oil changes. Oil level seemed to stay the same after running on the hose for 10-15 minutes.

 

[Scott Danforth]

how are the riser to elbow gasket surfaces?

how was the block winterized?

 

[Driv3r47]

We have gotten a lot of rain recently and there was standing water in the bottom of the boat for a period of time before I checked the bilge compartment and turned the pump on.
Don't think this would be an issue either but I did clean the entire engine compartment with degreaser and washed everything down a week before I noticed the milky oil.

 

[Driv3r47]

Riser to elbow surfaces look clean. Winterized on the hose with RV marine antifreeze as normal. Feeling confident that the block is not cracked but there is no way to tell for sure I guess without having it inspected by a mechanic, tearing it down or doing some sort of leakdown test. Wouldn't the motor run ruff, overheat or have high oil level on the stick if the block was cracked or the heads were bad?

 

[tpenfield]

Best thing to do is a leak test on the cooling system while the engine is still in one piece. Once an engine is disassembled, it is a lot harder to locate a crack/leak.

 

[wellcraft-classic210]

If you had a crack between a cooling water jacket and the oil compartment -- It would not necessarily affect the way the engine runs other than mixing with the oil as you are seeing.


Also -- Can you describe your winterization process in more detail -- As in -- Are you using muffs and RV antifreeze // or fully draining the block and exhaust manifolds by removing the plugs ?

 

[Driv3r47]

Winterized on muffs using rv/marine antifreeze and then drained the block.

 

[Driv3r47]

"Another source for milkshakes is a cracked oil cooler if you have one."

I checked and I do have an oil cooler on the boat. Didn't realize I had one. How do I tell if it is cracked or may be an issue? Thanks

 

[Bondo]

Any way to fully clean out the residue from the oily water in the motor without changing the oil and filter 5 or 6 times?

Ayuh,..... Welcome Aboard,..... Just run it up to temp, 'n the tiny amount of water will simply steam off,......

We have gotten a lot of rain recently and there was standing water in the bottom of the boat for a period of time before I checked the bilge compartment and turned the pump on.

Why, O Why don't you pull the bilge plug when you put the boat on the wagon,..??..??..??..??

Then no matter how much rain, nothing is damaged,.....

I checked and I do have an oil cooler on the boat. Didn't realize I had one. How do I tell if it is cracked or may be an issue?

Pull it off, 'n pressure test it,......

 

[wellcraft-classic210]

Regarding the winterization when you drained the block were you able to drain the exhaust manifolds buy pulling those plugs also ?

 

[wellcraft-classic210]

Nevermid about the manifolds -- I reread the posts above & see its not likely related -- Oil cooler testing seems of interest. I Will follow along to see.

 

[QBhoy]

9/10 times it will be the riser/exhaust manifolds passing or rotted through.
Exhaust shutters are unlikely to be the source unless you have a habit of reversing at 30mph or coming off the plane from high speed and shutting engine off before you come off the plane.
Time to look at the manifolds I’d say. All the best.