Help needed - oil became grey tacky, water mixed?

Ok just ran the engine at 1200 rpm for 10 min started fine, a small bit of white smoke at startup but that dissipated 5 min later. Oil is a mix of the sludge from yesterday diluted in the new oil. I am starting to remove it right now and redo an oil change.
Something puzzling me, no water out of the oil cooler by the oil fittings and coolant level in the expansion tank rose a bit like expected when engines warm up.

L

Talk about a cliff hanger!!! Hope it goes your way

Second oil change is done, replaced oil and filter and ran 1200rpm for something like 7minutes.
Coolant level rose a bit more what was expected from engine being warmer. Not a drop of smoke neither at startup nor while running.
No water out of oil cooler and oil looks cleaner than ever.
Usually when I do an oil change after running 5min oil is starting to turn black again because of oil remaining in engine. Now after 2 oil change in a row oil is perfect clear, I may notice still some trace so to be sure I will do another oil change next weekend (need to order extra oil filters).
I am totally lost about what could have done this.
The picture below is oil on the dipstick after second change and engine run:


L

The plot thickens. What rpm do you normally cruise?
Can you borrow a coolant system pressure tester?
Did you send out an oil sample? It not too late. You really need to know what was in there!

Most car shops like NAPA, O'Reilys... have 'cooling system pressure testing equip' you can borrow or rent

Usual cruising RPM is 1800 rpm.
Not yet send oil sample but I have all oil in jars and I will take sample of the grey sludge as well as oil after 2 changes to get that checked.
I will also remove the oil cooler and either make it tested or change it, it won’t be a bad thing anyway to have a new one.

But still I have no clue of what caused this at this point.

L

Lou, when was the last time you changed the oil? Last fall?

And when did you notice the milky oil? When was the last time it looked normal on the stick?

Have you put many miles on the boat this season?

Trying to determine when the moisture might have gotten in there.

Now some background info when this occurred if it can be of any help. It was our first weekend on the water after being back in water. Weekend was very hot and very very humid (more than 85% of humidity, 38C normal temp). First day checked oil level and oil was fine, full level and dark gold color. we started the engine, started immediately, no smoke, we went to the fuel dock and waited in line at idle for about 45 minutes before being able to dock to refuel. Then we departed for a 4h ride. Then morning after 3h ride to be back at the dock.
The day after we departed for a short 1h ride to an anchoring spot, checked the oil level and oil was a bit above full level but of the right color and texture. I put that to the fact that it was after an oil change (at haulout last year) and with a warmer day than ever I thought oil may have been a bit more fluid to go back in the pan.
The grey sludge has occurred during the 1h trip either round trip or returned trip.
Total 10h cruise in 3 days.

I must admit that if the oil cooler drip 1 drop every 30 second it can be a lot of water after 10h and may not be noticeable after 7min of run today.

L

As info again here are 2 video of the engine running at 1200rpm and at idle

https://youtu.be/B-i41t6p6o4

https://youtu.be/KKjMUC5pdNY

L

Ski in NC said:

Lou, when was the last time you changed the oil? Last fall?

And when did you notice the milky oil? When was the last time it looked normal on the stick?

Have you put many miles on the boat this season?

Trying to determine when the moisture might have gotten in there.

Click to expand...

Last oil change was mid October last year, 2 days before haul out for winter.
Notice Milky oil last Saturday. Looked normal the week before.
We did only 10h of cruise 1 week ago on saturday, sunday, monday and it was first cruise of the year.
The milky cream must have happened on the last stretch on the monday.

L

Another question, my engine is running at around 65C-67C at cruising speed. Do you see any problem to run it with the oil cooler bypassed?
I would like to do a 30min or 1h test run at cruise speed with the oil cooler out of the equation to see the result and check if get back some moisture again.

I also read that an engine running too cold can accumulate moisture in oil as it is not able to cook the moisture. What do you think of a 65C running temp? Low or normal? I tend to find this a bit low.

L

Lou -
One other possibility of water getting in the the oil is from the exhaust. It can happen in following seas or even at the dock with waves lapping up over your exhaust outlet.

This shouldn't happen with a well designed exhaust system, but many boats don't have enough rise prior to their water muffler or prior to their exhaust outlet.

It may be worth having a look at that, if you can't find another source of water ingression.

https://www.sbmar.com/articles/designing-a-marine-exhaust-system/

Lou_tribal said:

Another question, my engine is running at around 65C-67C at cruising speed. Do you see any problem to run it with the oil cooler bypassed?
I would like to do a 30min or 1h test run at cruise speed with the oil cooler out of the equation to see the result and check if get back some moisture again.

I also read that an engine running too cold can accumulate moisture in oil as it is not able to cook the moisture. What do you think of a 65C running temp? Low or normal? I tend to find this a bit low.

L

Click to expand...

It may be ok, but its not so much what temp the engine is running at but how hot the oil is. If you have a temperature "Gun" you can check the oil temp by "shooting" the oil filter and oil pan. As long as its not over 220 or so it should be fine.

Ken

This is very interesting, I forgot how to follow a thread without commenting therefore I am commenting. I understand that the oil is now clean and the oil side of the oil cooler is bypassed. I assume more testing is underway. Please continue to post.

Cliff Meima said:

This is very interesting, I forgot how to follow a thread without commenting therefore I am commenting. I understand that the oil is now clean and the oil side of the oil cooler is bypassed. I assume more testing is underway. Please continue to post.

Click to expand...

For sure I will continue to post.
More progress will take some time as I won't be back to the boat before next weekend, maybe weekend after depending on work.

L

Your engine normally runs at 65-67C (=150F). Is that kind of low? MY 280HP Cummins 6BTA typically ran at 185F at cruise (1750 RPM vs 260RPM WOT). What is normal for Lehmans?

65 C is very low for a fresh water cooled engine. Maybe you have a thermostat designed for a raw water cooled engine which is where they need to run to avoid salt water deposits in the block.

Running too low a temp will cause soot buildup as well as slightly lower efficiency.

But back to the main story: With clean oil and your cooler bypassed I would run it rather hard for an hour or so. Check the oil temps but with a block at 65 C I seriously doubt that your oil is too hot even without the cooler.

Then check for any new water in the oil. Also look in the coolant filler nozzle while under load and see if any bubbles are coming up. That is a sure sign of a blown head gasket.

But your problem is looking more like a one time raw water back up event. Look at the attached diagram which was developed for turbo charged engines, but relate it to your geometry with no turbo. If the clearance above the water level is too low then that can lead to back flooding.

Do you have a lift muffler? If so look at the second diagram of a well designed lift muffler system.

Both courtesy of Tony Athens.

David

Here's a tidbit from an engine guy.....

"#63 "The picture below is oil on the dipstick after second change and engine run:"

Still looks dodgy to me. I suggest he looks up "crackle test" on Google and test in a frying pan over his home stove. He may be surprised."

djmarchand said:

65 C is very low for a fresh water cooled engine. Maybe you have a thermostat designed for a raw water cooled engine which is where they need to run to avoid salt water deposits in the block.

Running too low a temp will cause soot buildup as well as slightly lower efficiency.

But back to the main story: With clean oil and your cooler bypassed I would run it rather hard for an hour or so. Check the oil temps but with a block at 150 C I seriously doubt that your oil is too hot even without the cooler.

Then check for any new water in the oil. Also look in the coolant filler nozzle while under load and see if any bubbles are coming up. That is a sure sign of a blown head gasket.

But your problem is looking more like a one time raw water back up event. Look at the attached diagram which was developed for turbo charged engines, but relate it to your geometry with no turbo. If the clearance above the water level is too low then that can lead to back flooding.

Do you have a lift muffler? If so look at the second diagram of a well designed lift muffler system.

Both courtesy of Tony Athens.

David

Click to expand...

I have a vetus waterlock right after the exhaust elbow, I would say 10inches below exhaust elbow, one like this one:

https://www.vetus.com/en/exhaust-systems/waterlocks/blokada-wodna-8336.html

Out from the waterlock exhaust is going almost horizontal than do a "goose neck" of about 14inches height and then down to the exhaust outlet. Exhaust throughull is something like 5 inches above water with a flap on it.

Not sure if this can result in engine water ingress from exhaust but can be a thing to check.

L

psneeld said:

Here's a tidbit from an engine guy.....

"#63 "The picture below is oil on the dipstick after second change and engine run:"

Still looks dodgy to me. I suggest he looks up "crackle test" on Google and test in a frying pan over his home stove. He may be surprised."

Click to expand...

This is a very good suggestion, thank you very much.

L

5" plus 14" above the waterline plus a flap sounds good to me. Then water backing up into your exhaust manifold is unlikely to be the cause of the water.


David

I think water ingestion from a muffler exhaust etc... on a diesel engine is going to have catastrophic results, so unlikely. Gas engine has some combustion chamber room to suck water in by the exhaust and not result in instant destruction.
Maybe steam vapor could build up, I dont know, still seems unlikely.

If you can not find anything wrong, then something unknown, one time event, not likely to repeat.

sdowney717 said:

I think water ingestion from a muffler exhaust etc... on a diesel engine is going to have catastrophic results, so unlikely. Gas engine has some combustion chamber room to suck water in by the exhaust and not result in instant destruction.
Maybe steam vapor could build up, I dont know, still seems unlikely.

If you can not find anything wrong, then something unknown, one time event, not likely to repeat.

Click to expand...

And if it was a back flow of water into cylinder I don't think that I would have been able to start the engine so easily right? I don't see how the engine could ave start right away if cylinders contained water.
But I need to find out what is the cause, I don't like the one time event as this could reproduce again without knowing hat is the cause.

Another cause I was thinking about is a cracked exhaust manifold that would make water leak in the engine when you stop and exhaust gases pressure drop but again would mean water in cylinders and would be hard to start the engine.

Just thinking out loud.


L

Greetings,
Mr. ps. Not to dispute your "engine guy" but the "grayish" bit at the end of the dipstick could well be a reflection through clear oil of a shiny bit of stick as opposed to the slightly oxidized bit of stick between ADD and the end. Say hello to your engine guy. I still owe him and his mate a fancy dinner. Maybe Wendy's. I don't think they'll let me back into IHOP again after what happened last time...

There is a tool that tests for hydrocarbons in your heat exchanger. If you have a blown head gasket hydrocarbons will leak into the cooling water. The tool should cost around $60.

Water in exhaust systems ends up in the cylinder and cause a hydrolocked engine. Oil cooler failures usually leave a trail of oil behind the boat, it is possible that your raw water pressure is higher than your oil pressure causing the water to enter the oil circuit. It’s also possible that the problem only occurs under certain conditions. I would have the oil cooler pressure tested by a radiator shop to be sure.

RT Firefly said:

Greetings,
Mr. ps. Not to dispute your "engine guy" but the "grayish" bit at the end of the dipstick could well be a reflection through clear oil of a shiny bit of stick as opposed to the slightly oxidized bit of stick between ADD and the end. Say hello to your engine guy. I still owe him and his mate a fancy dinner. Maybe Wendy's. I don't think they'll let me back into IHOP again after what happened last time...

Click to expand...

I cannot wait to know what happened last time at IHOP, knowing you it must be something interesting lol

L

Lou_tribal said:

And if it was a back flow of water into cylinder I don't think that I would have been able to start the engine so easily right? I don't see how the engine could ave start right away if cylinders contained water.
But I need to find out what is the cause, I don't like the one time event as this could reproduce again without knowing hat is the cause.

Another cause I was thinking about is a cracked exhaust manifold that would make water leak in the engine when you stop and exhaust gases pressure drop but again would mean water in cylinders and would be hard to start the engine.

Just thinking out loud.


L

Click to expand...

If you have an Autozone, they will let your borrow the pressure tester for the engine. You put it on the radiator cap, and hand pump the pressure. Then watch and see if the gauge drops.

tiltrider1 said:

There is a tool that tests for hydrocarbons in your heat exchanger. If you have a blown head gasket hydrocarbons will leak into the cooling water. The tool should cost around $60.

Water in exhaust systems ends up in the cylinder and cause a hydrolocked engine. Oil cooler failures usually leave a trail of oil behind the boat, it is possible that your raw water pressure is higher than your oil pressure causing the water to enter the oil circuit. It’s also possible that the problem only occurs under certain conditions. I would have the oil cooler pressure tested by a radiator shop to be sure.

Click to expand...

Instead of having it pressure tested, I will do a test run without it and then if the test shows a smoking gun, I will replace it right away, after 24 years of service it deserves a peaceful retirement in the box of "keep it even if you won't ever use it anymore". In fact I will either replace it and add bypass valves or totally remove it base on temp reading during my test run. And this will give the opportunity of correctly fixing both oil coolers that are now just hanging in the air as well as changing all the oil lines that show aging signs. When I get the hands dirty I like to do everything at once

BUT, is it the one responsible for my pain, that is the real question that keep me awake at night!

L

Is it possible over the winter a little coolant dribbled in, but laid in the bottom of the sump and only mixed with the oil when you ran it what, ten hours?

Oil laying in the sump will not be visible on the stick. Has to get mixed first.

Ski in NC said:

Is it possible over the winter a little coolant dribbled in, but laid in the bottom of the sump and only mixed with the oil when you ran it what, ten hours?

Oil laying in the sump will not be visible on the stick. Has to get mixed first.

Click to expand...

I think that this would be an explanation that fit perfectly as this occurred at the first ride. But what would be the cause of the coolant leak during winter? Seal? Crack in the block?
One thing, in spring I changed the water heater. When removed coolant hoses I attached them high to avoid pouring coolant everywhere. Similarly when I installed the new heater, I connected one hose and hang the other high to fill it with coolant, fill the heater, etc by gravity. Would there be any way that this caused coolant overflow in engine? I don't think so but I may be wrong.

L