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IMHO, if the head gasket is failing, my main worry would be exhaust gases leaking into the coolant - as this can cause erosion damage of the cylinder block or head. I had to repair the head gasket on a Toyota car, and the leaking exhaust gases had cut a channel about 1mm deep in the alloy head. It had to be TIG welded and then skimmed to repair.

You can easily do a chemical check for exhaust gases in the coolant. They sell kits quite cheaply.
 

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It was probably covered by the lab but did you consider your sampling method contaminating your samples. What method did you use? It is possible sea water or even previous oil samples came in contact with your collection container. I have sampled lots of water and have seen how very simple things can contaminate a sample. Humid salt air condensing in collection jar could cause contamination. Probably not, but Just one of many possible hypothesis.

I know it is simple but it could make all the worry's a moot point. If covered and probably was then disregard and good luck. Justin
 

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Discussion Starter · #24 ·
Many thanks to those who have responded with suggestions.

An update:

We went on across Biscay. We had the right weather and crew was available, so we changed the oil and did the crossing. I thought I could get it fixed in NW Spain, La Coruna. Mechanic there said he didn’t have time and referred us to the regional distributor in Vigo further south.

On arrival in Vigo several days later the Yanmar service supervisor and his mechanic were aboard and did a 45 minute very thorough visual inspection of the engine. They looked at the oil on dipstick and did swipes of oil on the top of the valve cover. They could find nothing wrong with the oil, and no indicaton of oil in the coolant. (Recall the French mechanic called the oil “beautiful”, these guys felt the same way). They aid there was no (visual) sign that any liquids were in the oil. They traced the cooling system looking for leaks and found none. Their conclusion: there was nothing wrong with the oil, the coolant or the engine. I got the sense that if they were from NJ they’d have said, “Fuggetaboudit”!

“But what about the lab reports”, I countered. They took copies and said they would send their write up (I have a copy) and the reports to the Netherlands Yanmar European HQ for comments/suggestions. I’ve heard nothing so far.

So, we continue on our path south and are planning on changing the oil every 40-50 hrs and continuing the lab tests.

I’ve started a very close monitoring of the coolant levels and for the last four times we’ve operated the engine I’ve seen virtually no drop in the coolant bottle (maybe a 1/6th inch--about the thickness of the mark I made on the bottle.

I have all the parts we need to do a complete tear down of the block, but I can’t seem to find a Yanmar mechanic who wants to take my money. We’ll keep trying as we move south. We have a 10 day stop in Lagos in southern Portugal and perhaps we will have word from HQ gurus by then.

If we were in the US near the guys who installed the engine and had access to all the high tech tools/methods described in some of the posts above I’m sure with time and money we could nail this problem down, but for now, the realities of long distance cruising in foreign lands prevail and we just have to keep moving so we’re positioned in November for the trade winds crossing.

I’ve had a couple of ideas that you might comment on:

1/ the engine is turbocharged and has an air cooler (seawater cooled). A small leak there could put small quantities of seawater in the intake air. The water would be vaporized in combustion and salts left on cylinder walls to find their way eventually to the oil.

2/ the rough seas we sometimes experience could be sloshing water from the muffler up the elbow. I doubt this as the installation team at NEB Portsmouth are very professional and I doubt they would not have engineered the exhaust system correctly.

3/ I wondering if my operating methods have contributed....we have a Gori prop (with overdrive) that allows us, when motoring in flat seas, to reach near hull speed at 2200 rpm (vs say 2800-2900 with the normal pitch). I’ve used the overdrive a lot (when fuel is $8 / gal one looks for savings where you can find them). The lower rpm reduces the pressure in the exhaust system and may allow a larger quantity of water to remain in the muffler when the engine shuts down. Follow that with sailing in heavy swell / rough seas (with engine off) and we may get the sloshing up into and beyond the elbow????

Will continue with updates when available.

Thanks again for the help thus far.
 

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Did the oil change colour and become a but mustard coloured?
Run the motor for a while, stop the motor, suck some of the oil out into a glass and let it sit for an hour or two.
Is it separating in to oil and water fractions?
If not, I would not worry about it.
 

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For the future though, do not buy sailboats with marine diesels with turbo chargers on them.
There is no weight penalty really with not having a turbo.
They are expensive, extremely high-revving, and not tolerant of salty air.
I avoid them like the plague.
 

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One possible route for raw water contamination (e.g. Water in oil) that I haven't seen mentioned re shaft driven raw water pumps. For water pumps not driven by a belt, the shaft has two seals, one for the oil and one for water.

A relatively simple way to check for exhaust gasses in the manifold is a combustion leak tester such as the UView 560000. Just samples the air in the manifold.

Josh
 

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thats a good update man

I do think you hit the nail on the head regarding engine use...

Im not familiar with that prop but lugging diesels which is effectively what you are doing and especially a turbocharged one(whats the point of the turbocharger if you are not hitting those higher rpms right?) can be a factor in increasing deposits, sludge and or minerals in your oil some of which can be "salts"

now all things aside like the shafts seals mentioned above of the water pump if all is kosher it could simply mean that your oil is sludging more than normal from slight "lugging" and this is normal

just change your oil more often, and if it where me and like most diesel marine engines reccomend every week or so do high speed load run for an hour or so at max sustainable speed with correct pitch from your prop

in other words yeah gun it properly and load it properly and you will decarbon and clear out any real bad stuff

you can also do this in combination with your favourite fuel stabilizer...

good luck

honestly I think you are fine...

ps. regarding the intake you can make a shield or secondary "AIRBOX" if you will to protect the intake even more from humidity and or slosh or whatever...however you have to be smart about it and have enough volume for when the turbo kicks in...
 

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Many thanks to those who have responded with suggestions.

An update:

We went on across Biscay. We had the right weather and crew was available, so we changed the oil and did the crossing. I thought I could get it fixed in NW Spain, La Coruna. Mechanic there said he didn't have time and referred us to the regional distributor in Vigo further south.

On arrival in Vigo several days later the Yanmar service supervisor and his mechanic were aboard and did a 45 minute very thorough visual inspection of the engine. They looked at the oil on dipstick and did swipes of oil on the top of the valve cover. They could find nothing wrong with the oil, and no indicaton of oil in the coolant. (Recall the French mechanic called the oil "beautiful", these guys felt the same way). They aid there was no (visual) sign that any liquids were in the oil. They traced the cooling system looking for leaks and found none. Their conclusion: there was nothing wrong with the oil, the coolant or the engine. I got the sense that if they were from NJ they'd have said, "Fuggetaboudit"!

"But what about the lab reports", I countered. They took copies and said they would send their write up (I have a copy) and the reports to the Netherlands Yanmar European HQ for comments/suggestions. I've heard nothing so far.

So, we continue on our path south and are planning on changing the oil every 40-50 hrs and continuing the lab tests.

I've started a very close monitoring of the coolant levels and for the last four times we've operated the engine I've seen virtually no drop in the coolant bottle (maybe a 1/6th inch--about the thickness of the mark I made on the bottle.

I have all the parts we need to do a complete tear down of the block, but I can't seem to find a Yanmar mechanic who wants to take my money. We'll keep trying as we move south. We have a 10 day stop in Lagos in southern Portugal and perhaps we will have word from HQ gurus by then.

If we were in the US near the guys who installed the engine and had access to all the high tech tools/methods described in some of the posts above I'm sure with time and money we could nail this problem down, but for now, the realities of long distance cruising in foreign lands prevail and we just have to keep moving so we're positioned in November for the trade winds crossing.

I've had a couple of ideas that you might comment on:

1/ the engine is turbocharged and has an air cooler (seawater cooled). A small leak there could put small quantities of seawater in the intake air. The water would be vaporized in combustion and salts left on cylinder walls to find their way eventually to the oil.

2/ the rough seas we sometimes experience could be sloshing water from the muffler up the elbow. I doubt this as the installation team at NEB Portsmouth are very professional and I doubt they would not have engineered the exhaust system correctly.

3/ I wondering if my operating methods have contributed....we have a Gori prop (with overdrive) that allows us, when motoring in flat seas, to reach near hull speed at 2200 rpm (vs say 2800-2900 with the normal pitch). I've used the overdrive a lot (when fuel is $8 / gal one looks for savings where you can find them). The lower rpm reduces the pressure in the exhaust system and may allow a larger quantity of water to remain in the muffler when the engine shuts down. Follow that with sailing in heavy swell / rough seas (with engine off) and we may get the sloshing up into and beyond the elbow????

Will continue with updates when available.

Thanks again for the help thus far.
Kind of lost track of the details. Did the lab verify that it is salt & not coolant in the oil? If so, I think your item #1 could be it? Is there any evidence of salt or corrosion in/on the turbo intake blades?

Paul T
 

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It does occur to me that there must be some small salt content in the air that's taken into the engine for combustion, given that at sea, salt is everywhere. Could it be contaminating the oil that way?
 

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I'm watching this thread with interest. As someone who makes their living diagnsing things, I can tell you that it is refreshing that you are a good historian with your issue and symptoms. I don't have the expertise to comment on what may be causing your issue, but I have some thoughts that may help you with the troubleshooting.

If you're worried about water entering from the stern while underway somehow contaminating the oil through the exhaust, you could possibly exclude this cause by changing the oil, and running the motor at the dock for a period of time. If the water/coolant ingress is still happening, it likely isn't from the water coming in through the exhaust.

Similarly with the issue of lugging, or over-propping you could try running the motor for a period without it being in gear and compare that to what happens when running in gear.

Personally, I would think that some of the UV dye would be really handy to have. Perhaps you could improvise it by removing the spongy guts of a highlighter pen and letting that soak in your coolant water for a while?

MedSailor
 

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I think you have a problem with your alarm. if it didn't go off till 245 or 250 that's way to hot. I have 2 temp alarms on my boat one is factory and I don't know what temp it trips at and the other I installed to sound at 200 degrees F. This gives me a little time to get the boat out of danger before shutting off. I wouldn't let an engine go over 212 F myself.
Can I ask what brand of gauge this is and where you got it? Seems like a really good idea if the factory one is set too high....

MedSailor
 

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This is what I used.

Racing Digital Temperature Controller Sensor Engine Alarm Oil Water Gauge Meter | eBay

it reads In centigrade so I had to get used to that but I put it where I can see it while driving the boat. It doesn't have great daylight visibility.

Be sure to connect the thermocouple to the block where there is a water jacket. The ends of the head are a good place.

These meters have relays for max and min temp so you can attach a separate buzzer or light or both. they do have a built in alarm, but installed in the panel that I built the plastic cover muffled the sound enough that I decided to install another sound device.

I set mine to sound at 90 C which is around 192 F.

If you keep your engine from over heating it will pretty much last forever. Virtually all major problems these engines have can be traced back to an over heat, Head gaskets, loss of compression due to cylinder scoring, leaking sleeve seals, water in the oil, oil in the water.
 

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Mark-
There is indeed more salt normally found in "marine" engine oils than in inland ones. And, more silicon and other "dirt" contaminants in the ones from inland. Vice-versa.

I once went nuts chasing down some contaminants in a water sample only to have someone finally say "And did you start by cleaning the glassware with Bon Ami? Ahuh, you didn't rinse it well enough." Could be that whoever pulled the OP's original sample wiped a sweaty brow or otherwise contaminated the sample, which is why a single sample is always suspect.

Mitch-
Race car drivers, who really don't have time to look at anything inside the car, traditionally mounted gauges so that a needle at the "normal" reading was oriented at the 12 o'clock position. Looks sloppy if you are reading the gauges, but makes it very much simpler to 'sweep' them with your eye, and notice if anything isn't "the same" as everything else at 12 o'clock. FWIW.
 

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I have been following this discussion loosely for some while and it occurred to me that before I made any major investments in anything once the usual suspects have been eliminated, I might have the oil I've been using for my oil changes tested/analyzed before I use/put it in the engine. You might discover that the contamination is in the oil to begin with and that your fears/worries about your engine are misplaced. It would not be the first time.

FWIW...
 

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Discussion Starter · #37 ·
A couple of quick responses....

1. There's no sign of "mustard" or "chocolate milk" oil.....it's clear. I know what that's like. Had a hydraulic lock once with the old engine after a 21 day passage in the trades. Five gallons of chocolate milk in the oil pan. I now start the engine once a day while at sea.

2. I have given up the overdrive for the time being. We'll run with standard forward pitch until this issue is resolved.

I've scheduled an appointment with the Yanmar guy in Lagos, Portugal. I'll post another update following that encounter.

Changed the oil at 50 hours today. Thank god this engine uses only 5 liters. The old six cyl. Nanni used 5 gallons.

Thanks again for the helpful advice and suggestions.
 

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Good logic, but how *salt* would get into a motor oil plant production line in the first place...That could only be sabotage on the line. Unheard of, AFAIK.
Perhaps, but, depending upon where the supplies are stored, there could easily be contamination. I have also seen, on the yacht moored next to us, an owner using a funnel for adding oil to his engine that he had used, only a short while earlier, to add coolant to his heat exchanger. Perhaps he "flushed" it before doing so, perhaps not. I do know of one test case in the Annapolis area in early 2000's where an oil sample straight from the bottle (Rotella 15-40) was pronounced to have indications of engine wear. Strange eh? When one does analysis, it is not unwise to have a "control" base as a reference from which to work, no?
 
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guys a lot of oils are recycled...so its easy to see where the "engine wear" theory might come from a new bottle of oil

aaaaaaaaaaaaaaaaaaaanywhooooo

OP think your doing the right things

stop the overdrive use...and if it where me give the engine a couple of runs for its money...you know balls to the wall.

however and we have not forgotten...you still have the one overheating incident which hopefully will not rear its ugly head anytime soon...

if you have a very good coolant temp gauge pay atention to it METHODICALLY after a long run and at max rpm etc...when really warmed up...any flicker should be considered abnormal.

regarding oil capacity on engines you can never have enough...pump capacity provided. jajaja
 

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Definitely agree that some sort of baseline testing would be helpful but salt air is likely the reason for a trace of salt in the oil. With the great number of cu' of sea air sucked in through an engine, it should be no surprise that some of that molecular salt gets into the oil. There should be some data on this kind of contamination. I would not be surprised if it's one reason for the frequent oil change interval of a marine motor. Similar industrial engines run more hours before recommending oil changes. I would keep an eye out for any sort of discoloration and look in the obvious places like pin holes in the riser but would really question an actual leak until there was more evidence. Both ends of marine engines are open to salt saturation all the time, even when sitting idle. That's why it's wise to plug both intake and exhaust when in storage. Salt air will corrode the inside of a marine engine quickly as well as rust your car out in a hurry.
 
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