Help High levels of soot in engine oil sample. ???

relentlesss

Member
Mar 27, 2016
34
Middle river MD
Boat Info
1996 Sea ray 450 Dancer 3126 cats garmin plotter raymarine radar
Engines
3126 Caterpillars 420hp
Could someone please tell me what this means. Motors are year 2000 3126 Cats 440 hours. Oil samples came back. Port motor fine. Stbd High levels of fuel soot in oil sample.............................................................................. ANALYSIS REFLECTS CONDITIONS / VALUES NOTED FOR MONITORING PURPOSES ONLY. EXCESSIVE level of FUEL SOOT present. CHECK

for air intake or exhaust restriction and proper fuel system settings. VISCOSITY is HIGH. Condition may be due to high operating temperatures,


excessive load, or over-extended oil drain interval. Other test results are satisfactory. CHANGE the OIL and OIL FILTER(s). RESAMPLE at the next


. This came up during survey. I haven"t bought the boat yet.
 
Sorry, I don't have an answer for you. Maybe someone will have something for you.
 
Did Cat do the survey? what did they say? join boatdiesel dot com - from what I understand its money well spent
 
When was the last time oil was changed?
Does the boat reach at least , if not over, rated RPM?

Soot is a by product of unburned fuel. As the report states, boat could have been run in an overloaded state for long periods which MAY reduce life of engine. Reading the report, it tells you what may have caused that issue.

Here is an article that talks about soot.

http://www.vehicleservicepros.com/a...ve-soot-levels-in-oil-can-cause-engine-issues
 
At Sea trial boat reached 2800 loaded down with 3/4 fuel 4 people. water and some personal stuff. bottom is clean and props are good also. Both transmission oils were real dirty.
 
Relent, 2800 looks good. If you could get FrankW to look at your numbers I think any questions you would have he could answer. In another thread today
there is a very good way to change Trans Fluids. Do a today's- "New post" search and you will find it. Good luck, JC
 
If the engines don't turn over 2800 rpm, then loading is probably ok.

The 3126 is prone to aftercooler fouling if you use the wrong type of oil. The 3100 series of Cat engines for some reason will clog up aftercoolers with the viscosity enhancers contained in multi viscosity oils. A clogged aftercooler restricts intake air and that will produce soot. So this may be something as simple as the previous owner using the wrong oil and not changing the oil as frequently as necessary….which would be annually on a 400 hour 2000 model.

Cleaning the after coolers is roughly a $2500 expense.

Unfortunately, you won't know if this is all of the problem until you clean the after coolers, change the oil/filters run about 25 hoiursunder normal operation conditions then resample the oil.

As a disclaimer, the above is from just your post and represents a most likely cause. If you are at the survey stage, you will probably want to involve a Caterpillar technician in the solution and advise you after he evaluates the engines in person because the other potential causes for sooting in the lube oil (overheating, overloading, lack of maintenance) can lead to very expensive repairs.
 
Frank Thank you. I pulled the trigger and bought the boat.
I got another 12k off the boat for the soot issue. I had a Viking princess sport cruiser before this boat. It also had the 3126 cats in it. You are correct 100%.When i bought the boat I would get heavy soot on the transom. I changed over to 30w Cat oil. WIthin 25 hours soot was all but gone. I should mention I also added oil catch cans to the Walker air seps.
 

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