Water in Oil...

[STraenkle]

So I was running the boat the other day and the oil pressure alarm went off. Limped back on 1 engine. The port motor had chocolate milk for oil. I figured it was the oil cooler because the coolant side was still full. Got the new oil cooler and replaced it. Changed the oil, still chocolate milk, changed it again, and again. Last night I changed it again and before starting the motor, the dip stick still showed signs of water in the new oil. Started the motor just long enough to get the oil pressure back, 45 PSI at idle. Shut it down and checked the oil level, then ran it up to temperature, say 15 mins, still holding 45 PSI oil pressure. Oil level did not change, so no oil leaving or water entering, that I could tell. No oil coming out exhaust. Engine sounds perfect, runs cool, if it weren't for the ugly oil, the engine would be perfect.

I am beginning to think that something else is wrong. The only places I can think that sea water could play with the oil is the oil cooler, or exhaust. But if the exhaust risers are bad, water would have to enter thru the cylinders and that would make the engine sound funny. I am I missing something? I knew it would take a couple oil changes to clean out the watery oil, but starting to think something else has to be wrong.

Oh the engines are Mercruiser MPI 496 CI or 8.1 Liter. The engine sounds great, runs strong, no bad noises, or overheating.

[Joseph Fikentscher]

Head Gasket?

[STraenkle]

I don't think it is a head gasket. Coolant level is unchanged and does not have any oil in it. I am fairly sure it the raw water in the oil. Engine runs perfectly, has power all the way to red line at 60% throttle, 5000 RPM and 35 to 36 knots.

[Carl]

Head gasket as Joseph mentioned...I'd do a compression test.
Coolant pressure test could be helpful too.

I am not sure how much water it takes to make a milky concoction. A quarter cup or so would be recovered with overflow tank.

Simple quick check...not definitive.
Cap on expansion tank...pull off, Stand back and start, bad leak will have water shoot out, so maybe something to do with a cool engine... No shooting water, look and see if you see little bubbles...could take till engine warms and thermostat opens. You'll know when you start to see water start to gush by...see no bubbles...good! See bubbles...no good.
See white smoke out exhaust?

I'd also be sure to check the old oil cooler to see if it has a leak. Plumb it to water line add some pressure and see if it leaks...
It leaks you know at the least you took care of one of the problems...hopefully all.
If it don't then you know problem is elsewhere.

City water pressure can be high in places...so if using a hose be careful not to give full pressure or you have a good chance of creating a leak instead of checking for one.

[Corey Mason]

I would do a leak down test too. It will tell you more than a compression test.

If you have water getting in into the cylinder, the water could be leaking past the rings if they are worn. Which, if they are worn it should be rebuilt anyways.

A compression test isn't a bad idea, but could read false...you could be getting a "wet test" on the cylinder with water leaking in and "dry test" on the others.

I would also pull plugs and check their condition as well.

Checking the oil cooler is a good idea too.

There's really only a few ways water can get to the oil.

[STraenkle]

Thanks for the ideas, but not a drop of oil in the fresh water side. The engine are not old and tried, hooked the computer up and they show 60% throttle at 35 knots kicking the rev limiter at 5000 RPM, yes I know way underpropped, but 33% throttle and 25 Knots worked for me. They are scary fast acceleration (425 Hp), could take people barefooting behind the boat. If it is a head gasket, I don't see how that much water could get in the motor and have the coolant level not change. It is possible, but I have had blown head gaskets before, engines misfired and was down on power. I have pulled the plugs and all look perfect. I need to test the old oil cooler and see if it truly had a leak, I guess then I will pull the exhaust and test that. Maybe take the oil and see what is in it. hell it could be fuel, which is a scary thought, but it does have a fuel cooler after the oil cooler.

After the first time and changed the oil, the engine had almost 8 quarts of "stuff" in the oil pan. only suppose to be 6.

[Carl]

Thanks for the ideas, but not a drop of oil in the fresh water side. The engine are not old and tried, hooked the computer up and they show 60% throttle at 35 knots kicking the rev limiter at 5000 RPM, yes I know way underpropped, but 33% throttle and 25 Knots worked for me. They are scary fast acceleration (425 Hp), could take people barefooting behind the boat. If it is a head gasket, I don't see how that much water could get in the motor and have the coolant level not change. It is possible, but I have had blown head gaskets before, engines misfired and was down on power. I have pulled the plugs and all look perfect. I need to test the old oil cooler and see if it truly had a leak, I guess then I will pull the exhaust and test that. Maybe take the oil and see what is in it. hell it could be fuel, which is a scary thought, but it does have a fuel cooler after the oil cooler.

After the first time and changed the oil, the engine had almost 8 quarts of "stuff" in the oil pan. only suppose to be 6.

Two quarts...even a foamy sounds like alot of water and you would miss that much in your reservoir...I'd think.

Risers and manifolds would have water sit in cylinders, have to go past rings...possible I guess, but I'd expect to see motor hydrolock with that much water going in. And your motor is new-ish...shouldn't have that much going past rings in short time...my 440's after 20 years still held water in cylinder with bad riser....no answers here....jus thinking,

Think your right to test Oil Cooler for leak 1st...maybe just had lots of foamy crud after first change and second contaminated quick. would be a nice answer.

[Kevin]

Scott,
Could it be fuel coolers leaking? What about a bad injector dumping lots of fuel and washing past piston ring? Stuck open thermostat running too cool causing excessive fuel? Just tossing ideas out there.

[Tony Meola]

Scott

Used to have 454's, we had risers go bad. She always started, sounded like a weak battery or bad starter until she pushed the water out. At first we thought it was a bad starter, since once the water was out it spun as normal.

That water did get into the oil. That did not ruin the engine, but caused the valve springs to break about a year or two after we had fixed it.

If you are getting water in to a cylinder then you should also see steam/smoke coming out the exhaust. Think about what a cars exhaust looks like on a cold damp day.

[Navatech]

Before I "donate" my $0.02 I'd like to verify a couple of things:

1) Your engine is fresh water cooled (closed loop) correct?!...
2) You use water in the closed loop (as opposed to a coolant) correct?!...

[Pete Fallon]

Scott,
Do a pressure test. Check your exhaust risers and the exhaust riser gaskets, then the heat exchanger, could be a bad tube inside exchanger , finally oil cooler. Sea Water has to be getting inside the engine thru either a gasket or O ring, maybe in the fuel cooler near the bottom inboard side of the block half way down the engine(starboard engine) port will be on the out board side.
I had a fuel cooler go bad, took a while to figure it out. Merc used Carter vane pump in the gasoline cooler they are not cheap the last fuel pump I bought was $350.00 each. Good luck

[Stephan]

Scott-
I hope you have good news.
I have older 454s and the oil filter is "remote" mounted for easier access to change the filters. I know when I warm the engines up prior to changing the oil that some oil remains in these lines. If I had real water contamination I would expect it to take several (many?) oil changes to clear.
Tell us you found the leak in the oil cooler you changed out and then tell us more about life with 850hp in your B31.
Best,
Stephan

[STraenkle]

First I want to thank everyone for the time they took to help. Great site isn't it?

I have been traveling the last few days, but still am not sure what is wrong. Yes closed loop coolant "fresh water" system. Use the red coolant that Mercury says to use. I have been hoping it was just going to take several oil changes to finally get the water out, due to pulling the oil thru dip stick tube only. But first thing is to make sure the oil cooler I took out, has a leak. If not, I still have an issue. The fuel cooler is a new thing to me, raw sea water runs thru a cooler to "cool" the fuel, just like the oil and tranny coolers. Guess it make more power that way. That could be the issue. I am most concerned about the exhaust at this point. If the oil cooler is fine and the sample I have of the oil does not have fuel, I will remove the exhaust and check the plugs this week end. I did notice once that I hit the starter and it kicked but stopped, hit the switch for both batteries and it started right up. I don't want to hydrolock it, so I am going to remove exhaust and plugs before I start it.

No smoke of any kind out the exhaust, no oil, just normal exhaust, never overheats or runs cold, right up to 180 in 5 minutes of idle and stays there. oil pressure has been fine, but have not taken the boat more than a couple miles out of the harbor till I am 100% sure it is fixed, or what it is doing.

[STraenkle]

As a foot note, last year was a very bad year for the motors, put in a new fuel tank which caused many issues, I don't believe it was the fiberglass tank, assured it was Ethanol rate rated, but all the crap that was in the tank after getting it, after flushing the tank and fuel lines dozen of times, the engine did run for October. I was down most of last summer from that, but was pretty sure that issue was gone after so many flushings. Had the heads off last year due to this, so head gasket still sit in my mind. been a bad few years for the boat. use to run 400 to 500 hours a summer, 30 last summer and maybe 30 this year. sucks, but I can't take it out if I don't believe it will be running 100%

[scenarioL113]

This is def a process of elimination. I had a buddy with a B26 that had twin mercruiser inline 6's and he had an engine get the oil contaminated with water like you have. His problem was the exhaust manifold on the raw water side. I guess it had a crack or rusted out area internally that the water leaked down into the exhaust port and filled a cylinder and got down into the crankcase.

This was a long time ago and I do not remember specifics but that is what happened for sure. After he replaced the manifold he drained the oil and refilled. I think he changed the oil a few times because there was residual water in the oil that was continuing to be a nusiance.

He did not take the boat out yet bc of residual water in the oil. After 3 or 4 oil changes he ran the motor at the dock idling with dipstick and the oil cap removed. This in essence boiled or steamed the water out of the motor after an hour or 2. Again this was many yrs ago and am remebering the best I can.

I am not sure if this is good advice for you but this is what my buddy did and he was all good to go after doing this.

Good luck

Frank

[Navatech]

Great site isn't it?

Absolutely yes!...

Yes closed loop coolant "fresh water" system. Use the red coolant that Mercury says to use.

Good... Perfect in fact... Coolant includes anti corrosion stuff... Have you looked at the coolant itself?!... Does it look the same as that in the other engine?!... Specifically, it doesn't look "washed out"?!...

I have been hoping it was just going to take several oil changes to finally get the water out, due to pulling the oil thru dip stick tube only.

Yes, it WOULD take several oil changes... And, at least one more if you didn't replace the oil filter prior to the first change... If you'd have asked me I would have advised the following procedure:

1. Remove all the polluted oil, remove the filter from the other engine and put it on this engine, remove the oil from the other engine and put in this engine, run the engine for a couple of minutes in idle...
2. Remove the oil and fill the engine with same amount (+ 1 quart) of diesel, remove the plugs and turn the engine 5 times for about 10 seconds each time... The diesel has enough lubricating capability to ensure your bearings won't suffer (especially as there's no load)... Check for "brown milk" (emulsion) on the dip stick and under the oil fill cap on the valve cover... Repeat if you see emulsion...
3. Put the plugs back, remove the diesel, remove the oil filter, fill the oil and put on a new filter... Run the engine again for a few minutes in idle... Check for "brown milk" on the dip stick and and under the oil fill cap on the valve cover... If you see emulsion replace oil and filter and repeat...
4. Don't forget to replace the oil and filter on the other engine!...

But first thing is to make sure the oil cooler I took out, has a leak. If not, I still have an issue.

Actually, determining where the water came from should have been the first step... It doesn't make sense to clean up what's going to get fouled up again... There's only so many places where water can enter into the oil sump in your closed loop system... Oil and/or fuel cooler, if it's one of these you're better off replacing the one on the other engine too because if they're of equal age once one goes the other is 99% sure to follow in short order... If these are OK it's time to check the risers... An unlikely (but not completely impossible) scenario is where you have a leak in the main (coolant) cooler AND a head gasket leak... You wouldn't see missing coolant because it gets replenished by sea water and, as long as it's a small leak, water in the cylinder CAN be pushed into the oil sump without causing hydrolock... In fact, if the leak is small enough you might not even get white exhaust smoke... But it will accumulate in the sump and cause the emulsion...

I don't want to hydrolock it, so I am going to remove exhaust and plugs before I start it.

FYI, big marine engines (think 2,000 HP and upwards) have special decompression valves on the heads... One for each cylinder... SOP is to open these before starting and turning the engine on the starter setup... This is to make sure that there's no water in any of the cylinders... Big ships will have at least one auxiliary (generator) unit as a "stand by" unit... Part of the weekly maintenance procedure would be to turn it over with open decompression valves...

[Carl]

. I did notice once that I hit the starter and it kicked but stopped, hit the switch for both batteries and it started right up.

That could be an important clue pointing towards risers.
I'd still check oil cooler...
Pulling plugs not a bad idea as you mentioned...give a turn with plugs out.
For giggles I'd do compression test too as plugs are out ....your there anyway. I can send you a compression gauge if you need one for awhile.

[Tony Meola]

Steve

If it is a riser and if you are getting water in the cylinder, then when you pull the plug from that engine, check it for water. Seems like the plug will be wet or when you crank it over it should push out water. Ours did.

As to what Nave said about changing oil, on the last and final oil change when you think that this is it, replace one quart of oil with one quart of Transmission fluid. Super hi detergent qualities and will clean everything. Don't be afraid to let it really one with the tranny fluid.

I used to dock next to a guy that owned a fleet of tow trucks. He used to put a quart in each truck when he changed the oil and ran them that way. Every 100,000 miles, as standard practice, he would rebuild the truck engines, and he claimed that he could eat off the pan it was so clean.

When I had a lifter hanging up, I ran my big blocks with a quart of tranny fluid for the season. Cleared up the stuck valve.

[STraenkle]

I would never change the oil without using a new oil filter. So that is 4 filters so far. The last change I used the 5 min oil flush to clean out everything. and thin the oil to get as much out as possible, still had the issue.

Carl thanks for the offer on the compression tester, I have one and will check the compression this weekend. Hoping I don't find a cylinder full of rust. That would be the end of the season most likely. I also have a leak down tester, but the generator is not going to run the compressor, so that is not an option. I am on a mooring.

Well tomorrow I will pull the risers, exhaust manifold, plugs, and pray. But first will plumb the old oil cooler to the compressor and see if it has a leak.

Let you all know what I find....

[Carl]

Some water in the cylinder is not the end of a season...unless you hydroloc and bend/break something. You should have a nice coating of oil on walls to deal with some water...for a short time. And as you said engine was running sweet.

Think once you pull exhaust you'll get your answers...or when you see if that oil cooler is leaking.

Good luck.

[Tony Meola]

Carl is right. Not the end of the season. Dear own maybe a week or t we o to get parts but that is about it.

[MarkS]

Tony where you a little whistled up at 10:42 last night when you posted? Not that its any of my bidness..........:)

[Joseph Fikentscher]

:)

[Tony Meola]

Strange

I have nothing to say

[MarkS]

See now here would be a good place for a "Like" button.

Or from Scott's perspective a " You bastards hijacked my post" button.

[LesBrown]

Many years ago in a past life I had a small block chevy that was getting water in the oil. Ran perfect, this was a race engine, finally found that it had a pin hole leak low in the cylinder below the ring travel area. water was running down the side of the cylinder into the sump. Finally found it by taking the pan off and pressuring up the radiator and seen water dripping through the rods and crank. We figure that with a .060 overbore that the cylinder wall had a thin spot that caused this. I know that this is not a way that you would be able to check your block due to no room. Sodium Silicate, and ran the motor two more years.

[STraenkle]

Well, pressurized the oil cooler with a garden hose at 60 PSI, not a drop leaked. So now I have a spare oil cooler. Took all the plugs out and starboard side of the port engine blew water all over the place when I cranked it. Took the exhaust off on that side, water poured out of the exhaust, plugs on that side had rust also. Pressure tested the exhaust, water pours out of it. Good news is, found the issue, bad news is, it is cast aluminum and very expensive. $800. ordered one and sprayed fogging oil in the cylinders and exhaust ports. cranked the engine and sprayed again. Hopefully that will coat it long enough till the exhaust gets here.

[lobsta1]

Scott, I would also pull the valve covers, spray everything down with WD40 to clean up the valve train. Then Corrosion X or similar on the valve train.
Good Luck
Al

[Fishin Tom]

Just a thought--

If I am not mistaken that motor has the intake gasket with o-ring seals on it and they are known to fail. Felpro makes a better replacement gasket which eliminates the o-ring type seal. Worth checking before major surgery.

Tom Oakes