Milky oil in Crankcase

[sunchaser]

Once the valve cover is removed Sea Foam is a great cleaner for that exposed area. I've used it on several ocassions for this exact happening - water in oil.

 

[SteveK]

Many engines, not just diesels, have stretch bolts in various places, not just the cylinder head. These bolts cannot be re-torqued or re-used. Know what you have first. (retired mechanic with 40 years experience)

An over torqued bolt could stretch, become weaker.
Perhaps that is why 135 says not to torque again, they may be onetime bolts.

 

[Bugaboo]

Have you determined it was the oil cooler if so your idea sounds OK not what I would do but it’s your motor whatever you think.If you haven’t determine the cause what’s with all the flushing .I understand the pickling part unbolt your head inspect your head gasket jack your engine up as high as you can get it drop your oil pan clean and inspect with those crossed fingers

 

[OldDan1943]

If you are going to the trouble of removing the head, get it resurfaced at a good machine shop.

 

[Bugaboo]

If you are going to the trouble of removing the head, get it resurfaced at a good machine shop.

Now we’re thinking .I know how devastating losing an engine is but it is what it is . Pressure in your cooling system is usually much less than your oil pressure unlikely that water is going to make it into your oil more likely oil will be in your water seeing how the pressure in the radiator is somewhat below 15 psi .I know the pressure remains when the engine isn’t running I still don’t think it’s your oil cooler what do I know

 

[SteveK]

Now we’re thinking .I know how devastating losing an engine is but it is what it is . Pressure in your cooling system is usually much less than your oil pressure unlikely that water is going to make it into your oil more likely oil will be in your water seeing how the pressure in the radiator is somewhat below 15 psi .I know the pressure remains when the engine isn’t running I still don’t think it’s your oil cooler what do I know

Until oil is tested for coolant or raw water ingested, the type of water is a guess.
I think the oil cooler was replaced or checked already.
That said raw water oil cooler pressure may be higher than oil pressure IDK. But if the cooler has a hole big enough for oil or water to pass and the thru hull is left open I suppose water can weep into the oil.

 

[Bugaboo]

Thank you for reminding me that the coolers are on the raw water circuit brain fart I guess .There is little to no pressure on that circuit because it flows freely to the exhaust the likelihood that the cooler is causing this problem is very very very small imo

 

[OldDan1943]

Consider having to oil cooler pressure tested.
If it fails, replace or find the leaky tubes and plug. You should be able to plug about 1/3 the tubes without worry (navy standards)

Did you do a compression test on the the engine?

 

[carpedatum]

I (sadly) have gas engines, so take this story for what it is worth in this context (perhaps not much).

Our old boat came to us with two "refreshed" inboard Mercruisers, and I eventually came to understand that "refreshed" meant she'd been fitted with two replacement long blocks, installed by the PO and a mechanic who is a liveaboard on the next dock over. Sea trials and inspections went just fine, but the first trip out with a training captain saw trouble with both engines.

To keep a long story short, I eventually ended up replacing the intake manifold gaskets on both engines. Obviously this isn't a problem for a diesel, however I did have one surprise along the way that may translate.

I learned of the need to replace the starboard engine's intake gasket set because very modest coolant loss and oil the color of chocolate milk were occurring at the same time. Other tests confirmed that the issue was most probably with the intake manifold gaskets. After replacing the gaskets and torquing down new bolts to factory specs per the pattern in the Mercruiser manual exactly, then changing the oil and running the engine briefly, I wasn't surprised to see still-milky oil.

What did surprise me is that it took no less than _seven_ oil changes before I saw a perfect-looking result on the dipstick. Only after three did I see any meaningful improvement, and that kept me going. Things got incrementally better with each oil change/engine run cycle after that.

I certainly can't say whether diesel fuel or biodiesel is your answer, but I sure did recycle an awful lot of Mobile 1 over a couple of days, and would be inclined to try another path given a similar problem in the future. Best of luck with it!

 

[jsanacore]

I had an 1965 Lehman 95hp 6cyl in an Alden Motor Sailor - This same engine block later developed into the 120 and then the 135 - So we are talking about the same engine, basically - When I would run up and down the East Coast in cool to cold weather , I would sometimes run into temperature differences in the engine compartment from the rest of the boat - The temperature difference caused condensation to form in the valve cover. The water (from the air in the engine compartment) would turn the oil sump oil tan - I would change the oil a couple of times, and then try to keep the engine compartment temperature more constant using a heater - This worked -- VBTW - Before I realized that this was the cause of the oil sump water, I tried everything - Compression tests - New Head gasket - A retired diesel mechanic who was at least as old as I am now suggested that the temperature differences might be the problem - He was right - Old can be good

 

[Bryant]

Milky oil

I have an Albin 40 powered by twin Lehman 135 that has run perfectly for the 4 years that we've owned it. Checking the fluid levels prior to a scheduled cruise, I found that my port engine appears to have water in the crankcase oil. The oil, which is usually a dark brown/black was almost tan, like coffee with milk. 3 weeks ago, we returned from a week long cruise during which the engine ran flawlessly. I make it a habit of checking all the fluid levels daily (trans/coolant/engine oil/diesel in Racor filters)before starting engines. Our last day out was a short 3 hour cruise home. I know that prior to the run home, the oil level/color was normal, so the water had to enter the crankcase sometime during the last 3 hours. Since the engine ran flawlessly, (No loss of oil pressure and engine ran at normal temp) I surmised that the oil cooler was the culprit, as it was the only place that the water/oil are in close proximity, so it was replaced.

I totally drained the engine oil, and replaced it with fresh oil, started the engine and ran it for almost 15 minutes (No problem starting and oil pressure was normal). I shut down the engine and the oil was once again light tan. Drained it again, and it was still showing some water. I read somewhere that you should drain the crankcase 3 times to insure all the water has been removed. I'm letting the engine sit after adding fresh oil, hoping that the oil will rise to the top, with the water at the lowest point in the crankcase. I checked it again by just draining a small amount this morning and what was drained appeared to be more 'watery' than oil. I plan on leaving the fresh oil in the crankcase and not running the engine in hope that perhaps the water would settle to the bottom of the crankcase. I read that you could also pickle an engine with diesel fuel in the crankcase. This seems like a possible course of action, as the diesel is much lighter than the straight 30w oil required. Additionally, the cost of filling and draining the crankcase numerous times is considerably less.

Opinions and feedback greatly appreciated.

Pretty sure you have a blown head gasket. What does the inside of your oil filler cap look like?

 

[ronobrien]

I have an Albin 40 powered by twin Lehman 135 that has run perfectly for the 4 years that we've owned it. Checking the fluid levels prior to a scheduled cruise, I found that my port engine appears to have water in the crankcase oil. The oil, which is usually a dark brown/black was almost tan, like coffee with milk. 3 weeks ago, we returned from a week long cruise during which the engine ran flawlessly. I make it a habit of checking all the fluid levels daily (trans/coolant/engine oil/diesel in Racor filters)before starting engines. Our last day out was a short 3 hour cruise home. I know that prior to the run home, the oil level/color was normal, so the water had to enter the crankcase sometime during the last 3 hours. Since the engine ran flawlessly, (No loss of oil pressure and engine ran at normal temp) I surmised that the oil cooler was the culprit, as it was the only place that the water/oil are in close proximity, so it was replaced.

I totally drained the engine oil, and replaced it with fresh oil, started the engine and ran it for almost 15 minutes (No problem starting and oil pressure was normal). I shut down the engine and the oil was once again light tan. Drained it again, and it was still showing some water. I read somewhere that you should drain the crankcase 3 times to insure all the water has been removed. I'm letting the engine sit after adding fresh oil, hoping that the oil will rise to the top, with the water at the lowest point in the crankcase. I checked it again by just draining a small amount this morning and what was drained appeared to be more 'watery' than oil. I plan on leaving the fresh oil in the crankcase and not running the engine in hope that perhaps the water would settle to the bottom of the crankcase. I read that you could also pickle an engine with diesel fuel in the crankcase. This seems like a possible course of action, as the diesel is much lighter than the straight 30w oil required. Additionally, the cost of filling and draining the crankcase numerous times is considerably less.

Opinions and feedback greatly appreciated.

It is a bit of work but if you remove the injectors you can look into the cylinders with a cheap bore scope attachment for your smart phone. You could then pressurize the fresh water jacket and look for leakage into the cylinders. The Lehmans had some minor issues with porosity of the cylinder walls, which would require machining and dry liners installed. Quite a bit of work but the diagnosis would be the surest way to ascertain for sure where the problem stems from. If you do pull the injectors, look at them carefully as they come out. That may give some evidence of the suspect cylinder, if that is indeed the problem. Good luck.

 

[sunchaser]

Pretty sure you have a blown head gasket. What does the inside of your oil filler cap look like?

The oil filler cap will show water droplets due to water or coolant in the oil. Questions remain as to whether coolant or raw water and once determined from where.

 

[twistedtree]

Test the oil to see if it's coolant, fresh water, or salt water in the oil. Each of those will send you down a completely different path.


Fresh water would indicate the condensation problem described earlier.


Salt water will focus you on the raw water cooling circuit, and coolant will focus you on the engine core.


Engine oil coolers I think are more typically cooled by engine coolant, not raw water. It's the gear oil that's cooled by raw water. But I don't know the Lehman's so they may be different. If you replace the gear oil cooler, well, that doesn't interact with the engine oil in any way, I don't think.


So test the oil so you know where to focus your attention. Then I'd start pressure testing things until locating the problem.

 

[ronobrien]

Test the oil to see if it's coolant, fresh water, or salt water in the oil. Each of those will send you down a completely different path.


Fresh water would indicate the condensation problem described earlier.


Salt water will focus you on the raw water cooling circuit, and coolant will focus you on the engine core.


Engine oil coolers I think are more typically cooled by engine coolant, not raw water. It's the gear oil that's cooled by raw water. But I don't know the Lehman's so they may be different. If you replace the gear oil cooler, well, that doesn't interact with the engine oil in any way, I don't think.


So test the oil so you know where to focus your attention. Then I'd start pressure testing things until locating the problem.

My Lehmans are raw water cooled oil, engine & trans.

 

[SteveK]

Condensation.
Can we discuss how this occurs in a closed engine, as in closed to outside air except the intake, perhaps the crank ventilation breather, what else. I see condensation on the exterior.

My engines and engine room get hot regardless of the outside temp. It takes a while to cool down, it is not sudden. What I am having difficulty understanding is how moist air of any quantity can enter to block valve cover etc. in enough quantity to become noticeable as milky oil.

Any thoughts?

 

[KnotYet]

Condensation.
Can we discuss how this occurs in a closed engine, as in closed to outside air except the intake, perhaps the crank ventilation breather, what else. I see condensation on the exterior.

My engines and engine room get hot regardless of the outside temp. It takes a while to cool down, it is not sudden. What I am having difficulty understanding is how moist air of any quantity can enter to block valve cover etc. in enough quantity to become noticeable as milky oil.

Any thoughts?

Two sources of moisture come to mind:
Outside air with high humidity and the water that is the product of combustion.

A marine engine that is overcooled or used at a light load may not generate
high enough sustained temperatures to drive off the moisture accumulation.

 

[sunchaser]

Water in the oil, as the OP has suffered, will show up as droplets in the valve area and on the oil fill cap. I've seen it several times, the last due to a leaky after cooler that put sea water into charge air. One other time it was due to a bad exhaust elbow leaking into #6 cylinder. One more direct experience, a cracked block.

But, I've no idea from where the water is emanating in the OP's case absent oil data. About half a dozen real world experiences come to mind.

 

[twistedtree]

My Lehmans are raw water cooled oil, engine & trans.

Thanks. Haven’t see that before.

 

[SteveK]

Liquid water in quantity entering the oil will make it milky, that is uncontested.
My question remains, condensation requires moist air to enter the valve cover or oil pan in order to condensate as the metal cools. That seems like a onetime event with a tiny amount of moisture. Start the engine and that is expelled via the valve cover breather.

 

[diver dave]

Liquid water in quantity entering the oil will make it milky, that is uncontested.
My question remains, condensation requires moist air to enter the valve cover or oil pan in order to condensate as the metal cools. That seems like a onetime event with a tiny amount of moisture. Start the engine and that is expelled via the valve cover breather.

Crankcase oil expands and contracts with temperature. The inhale cycle clearly could bring in wet air. And, oil will absorb water vapor. But a motor doesnt have a large supply of oil. I work with automated gas dryers trying to keep oil dry. But, we are talking up to 16,000 gallons of oil in a single container. With a significant level change with temperature.

 

[BruceK]

My Lehmans are raw water cooled oil, engine & trans.

I saw an IG32 with twin 4cyl 80hp Lehmans, raw water cooled. On starting, some solids came out the exhaust, mainly looked like shell. No heat exchangers must be good, but brings its own issues. How do you find them?

 

[SteveK]

I saw an IG32 with twin 4cyl 80hp Lehmans, raw water cooled. On starting, some solids came out the exhaust, mainly looked like shell. No heat exchangers must be good, but brings its own issues. How do you find them?

I would be surprised if a Lehman raw water cooled lasted this long in salt water.
Usually meant for lakes, though I had raw water cooling engine once, The exhaust manifolds went and the oat soon after

 

[ronobrien]

I saw an IG32 with twin 4cyl 80hp Lehmans, raw water cooled. On starting, some solids came out the exhaust, mainly looked like shell. No heat exchangers must be good, but brings its own issues. How do you find them?

I don't have much of an opinion. I bought the boat in Nov 2020 and the only time I have on it is the 7 hours to run from CT up to RI last spring. It is on the hard for about 2 years for refit. I did remove the engine exchangers and rodded them out to be sure I wouldn't have an issue during the trip. I do not like the fact that there are no strainers on the raw water intakes, which is one issue that is being addressed during the refit.

 

[Larry M]

I would be surprised if a Lehman raw water cooled lasted this long in salt water.
Usually meant for lakes, though I had raw water cooling engine once, The exhaust manifolds went and the oat soon after

I agree. A raw water cooled engine has 1 pump vs 2 and no heat exchanger. It was mentioned rodding out the heat exchanger so this would not be a raw water cooled engine though it is using raw water to cool the engine but not directly. That's being done via a heat exchanger. I know, confusing but no big deal.

 

[ronobrien]

I agree. A raw water cooled engine has 1 pump vs 2 and no heat exchanger. It was mentioned rodding out the heat exchanger so this would not be a raw water cooled engine though it is using raw water to cool the engine but not directly. That's being done via a heat exchanger. I know, confusing but no big deal.

I have realized that one of my previous comments wasn't clear. The engine HEAT EXCHANGER, as well as the oil & trans heat exchangers are raw water cooled. Another commenter wrote that he thought the oil & trans heat exchangers were fresh water cooled. The engine ITSELF is NOT raw water cooled. Sorry for the confusion.

 

[Larry M]

I have realized that one of my previous comments wasn't clear. The engine HEAT EXCHANGER, as well as the oil & trans heat exchangers are raw water cooled. Another commenter wrote that he thought the oil & trans heat exchangers were fresh water cooled. The engine ITSELF is NOT raw water cooled. Sorry for the confusion.

No problem. Let's figure out what happened and get it fixed.

 

[FF]

IF you get desperate in finding the leak, the refrigeration folks have oil that can be added that will glow with black light.

Might help finding a tiny leak.