Perkins 6.354t raw water circulation.

The friendliest place on the web for anyone who enjoys boating.
If you have answers, please help by responding to the unanswered posts.
Joined
Jan 25, 2013
Messages
1,357
Location
US
Vessel Name
Northern Lights II
Vessel Make
Bayliner 3870
A friend has a mid 70s houseboat with Perkins 6.354t diesels. The starboard engine was a gallon + over fill in the crankcase with water, not coolant. Before doing anything to diagnose the problem he pulled the head. There was no indication of a blown head gasket and that’s when he called me. I advised him to get a oil sample, the oil had been drained but he was able to suck enough out to sample. It showed water dilution. I told him the oil cooler was a possibility and another was the exhaust manifold if it was rotted between the exhaust side and water side. Both tested good no problems. He also had the inter cooler checked and it’s ok.
I’ve run out of possible culprits, does anyone have any idea how water can get get into the oil? It didn’t happen slowly it was quick oil was ok and a week later way overfill. I can’t believe vandalism but can’t think of another way for water to contaminate the oil. Any help is greatly appreciated.
 
Is this the manicooler design? Also, is the oil cooler raw water or coolant cooled? Lastly, how did he check integrity of oil cooler?
 
Raw water is plumbed through the oil coolers, inter cooler, heat exchanger and exhaust manifold. He had the oil coolers and and exhaust manifold checked by a reputable radiator shop.
 
Raw water is plumbed through the oil coolers, inter cooler, heat exchanger and exhaust manifold. He had the oil coolers and and exhaust manifold checked by a reputable radiator shop.

If the manicooler design, they are very very difficult to pressure check alone for leaks as "crack" expansion with heat often missed.
 
Is the boat in salt or fresh water?

If salt water, was sodium elevated in analysis? In other words, raw water or freshwater in oi
 
Another question I have is, how long did it take for this water to appear? Was it last looked at a day ago, a week ago, a month ago, or a year ago? How many hours of operations since then?

In other words did it accumulate while the boat was running and underway? Or while it was stopped overnight at the slip? Or over the last year and no one knows how or when?

I doubt it is the case here. I suspect there is a problem somewhere. But, as a random unlikely thought, in case the unlikely becomes probable, on manicooler systems where it runs parallel to the engine block, someone could have added water to the oil fill thinking it was the header tank and low. I can't imagine. But, have certainly seen crazier.

If everything has been pressure tested, I'd assemble it do a chemical exhaust gas test and a cooling system pressure test, both unlikely to show anything given these symptoms but cheap via Harbor Freight tools, and then run it and see if it does it again and, if so, if it rushes in or not or comes in slowly. If you pull the manifold shortly after it happens, if there is water there, etc.
 
Last edited:
Ever heard the story of the (applied) computer scientist, the engineer, and the technician driving down the winding mountain road?

They are coming down this steep, narrow winding road. Cliff drop off on one side. Mountain wall on the other side. Steep and slippy dirt path going down.

Then, they loose their brakes. The car starts going faster and faster and faster. It slides and slips as it steers. Rocks and dirt can be heard tumbling off the cliff. The mountain wall is menacing. Down they go. Faster and faster.

Miraculously, they make it to the bottom. The coast along the road, into the grassy median, and come to a stop. The engineer, the technician, and the computer scientist get out of the car, wipe their brows, and kiss the ground in relief.

They laugh for a moment. And then, they look at the car. They remain a long way from home.

The technician exclaims, "I know I can fix it, but I don't have my tools." The engineer pulls a small pad from his hip pocket, takes a pencil from his breast pocket, and advises, "Hold up. We should take some measurements, make some other observations, and document this first".

The computer scientist looks at each of them with an expression of disgust and confusion and says, "What are you talking about? We should push it back up the mountain and see if it does it again."
 
Last edited:
Another question I have is, how long did it take for this water to appear? Was it last looked at a day ago, a week ago, a month ago, or a year ago? How many hours of operations since then?

In other words did it accumulate while the boat was running and underway? Or while it was stopped overnight at the slip? Or over the last year and no one knows how or when?

I doubt it is the case here. I suspect there is a problem somewhere. But, as a random unlikely thought, in case the unlikely becomes probable, on manicooler systems where it runs parallel to the engine block, someone could have added water to the oil fill thinking it was the header tank and low. I can't imagine. But, have certainly seen crazier.

If everything has been pressure tested, I'd assemble it do a chemical exhaust gas test and a cooling system pressure test, both unlikely to show anything given these symptoms but cheap via Harbor Freight tools, and then run it and see if it does it again and, if so, if it rushes in or not or comes in slowly. If you pull the manifold shortly after it happens, if there is water there, etc.



It happened sometime after it was slipped after making a fuel run to another marina and less than a week later when he returned to the boat. I think this happened quickly after the fuel run. His Perkins have heat exchangers not manicoolers. The manifolds are what I call “wet manifold”
with raw water running through it and out the exhaust.
The plan at this time is to reassemble the engine and put as many hours as possible between now and time to winterize here on the upper Mississippi. He will also take oil samples every 20 - 25 hours to try to find out if the problem is still present. The only parts that could be compromised to allow water into the oil are the oil cooler, exhaust manifold or inter-cooler. All of these have been tested, I doubt the inter-cooler could be to blame because any water that got into the charge air would go out the exhaust as steam. I’am really at a loss as to what the problem could be. I’am starting to lean towards the vandal theory.
 
I find it hard to imagine that much oil getting into the engine on a bat that ain't running. But, what to say? It is what it is, I guess.
 
He removed 4.5 gallons of oil and water before starting the tearing it down. It was fine before the cruise across the river about 1 hour run time there and back. Less than a week later he found it way over the fill mark. A few days before we did the fuel run we went 20+ miles up the Illinois river from Grafton and back. I have a difficult time understanding how that much water could of entered the engine sitting in the slip which seems to be what happened. When he tore it down the oil wasn’t like milkshake the water was sitting on the bottom of the pan. Is this because it hadn’t been run with the water or because it was straight water not coolant?
 
" He removed 4.5 gallons of oil and water before starting the tearing it down" I get 9-10 quarts out of our T6.354 for oil change so he got roughly the same amt of water as oil from when drained for tear down ? Just asking so I follow / understand this correctly.
 
" He removed 4.5 gallons of oil and water before starting the tearing it down" I get 9-10 quarts out of our T6.354 for oil change so he got roughly the same amt of water as oil from when drained for tear down ? Just asking so I follow / understand this correctly.



That is correct, he guessed it was 2" over the fill mark on the dipstick.
 
I find it hard to imagine that much oil getting into the engine on a bat that ain't running. But, what to say? It is what it is, I guess.

Wow. I was having a fat thumb and small phone moment. I intended to write, "It is hard to imagine that much water getting into the engine oil in a boat that ain't running. But what to say? It is what it is, I guess."
 
River Cruiser;807334 I doubt the inter-cooler could be to blame because any water that got into the charge air would go out the exhaust as steam. I’am really at a loss as to what the problem could be. I’am starting to lean towards the vandal theory.[/QUOTE said:
I have first hand experience with a failed after cooler and resultant some raw water migrating to oil. Enough to turn oil to chocolate milk but not raise the oil level much. Water in oil will turn oil milky real quick. If not milky the oil is being diluted with diesel.

A few oil changes, visual changes and oil analysis will tell the tale. Maybe owner induced by adding coolant to oil fill rather than coolant tank?
 
Last edited:
The oil analysis was water contamination. His 1st thought was fuel because he had a injector fail and siphon fuel into the crankcase one time. We start putting everything back together tomorrow morning.
 
I assume, based on model number, this is a vertical engine. I think you have checked/tested the proper items so far. The oil cooler is the most likely suspect and if you trust whomever tested it that has been eliminated.
Barring siphoning, ask yourself, where is the static waterline on the engine? This could help eliminate other items.
If no mistake or sabotage, what about a large wake from a passing boat running up the exhaust and into the turbo, manifold & cylinders and then filtering down, by the rings over time, into the crankcase. As an example, many boats that have run for years without problems, fill their crankcases when anchored in a seaway in the trades. Water enters the exhaust as usual but without a proper loop aft, finds its way to the engine, filling a waterlift muffler even and eventually the engine as the vessel hobbyhorses at anchor. The same situation may have briefly occurred at his marina.
 
Brooksie raises a good point about the exhaust backfilling the engine. If all the other potential sources are eliminated such as the oil cooler, a head gasket and so on leaking then have a good look at the exhaust. FLat runs from transom to mfld can be filled even if for years it never did. Normally a water lift will protect but some situations can overwhelm them.


What was the oil test showing for potassium and sodium levels.
Can you post the entire report as the ratio between the two can help point to either seawater or coolant. That would narrow the potential sources. Ski in NC has given those ratios many times which is where I got them.

See link
 

Attachments

  • Salt or coolant testing.doc
    23.5 KB · Views: 27
The exhaust outlets on the transom are above the swim plateform. I see no way any wake in the marina or on the river for that matter could induce water into the engine.
 
Shame he didn't do a compression test first-off. Looking at a head gasket often doesn't tell the tale.
I would think that most of the items he checked could make the oil milky due to leakage while the engine is running but not really pour raw water right into the crankcase. Except the manifold on a vertical engine. I would get a second opinion on the manifold... They are raw water cooled and 5-7 years max service life.
 
The fact that the oil and water are not mixed is a big clue, pretty much eliminates the raw water system as a suspect. (Unless, as mentioned above, the motor lives below the waterline)
For my $.02 worth, How about a bilge pump failure or a delayed startup of same?
The ER could have flooded, with a sticky float switch kicking in late.
The water could have then entered through the dipstick port.
 
Air pressure test

The ONLY other possibility is cracked block -doubtful. Air pressure test it will locate the leak (my guess is the inter cooler)
 

Latest posts

Back
Top Bottom