% of Diesel In The Oil. How High Can It Go

[MMeilicke]

I sent an e mail to Blackstone and Cummins asking about upper limits of diesel in the crankcase. I thought the replies might be of interest.



Blackstone:



"Our problem level for too much fuel in the oil starts at 2. 0% of the sample. At this level, it can be from too much idling, lots of city driving or taking the sample right after starting the engine. When we find fuel dilution consistently above 2. 0% it usually means a problem with the fuel delivery system like the injectors or injector seals. We have not seen too many instances in the type of diesel the you wrote about. Cummins makes a sturdy engine and they have a good warranty program to cover things like a faulty injector and such. thanks for your question. "



Cummins:



"5% fuel in oil dilution is sufficient to justify investigation according to the Oils for Cummins Engines Bulletin (No. 3810340-06). "



Interesting. Anyone have any idea what the link is to the referred bulletin?

 

[jelag]

Great post, thanks... .

 

[2Rowdy]

I have done 2 uoa through blackstone the first had a trace of fuel, the second had 3%. They had reply of idling to much that statement. It seems to be the 6. 7 has more fuel in oil. But I did let it idle for 5 to 7 minutes before I pulled the sample this last time. Just my . 02 worth.

 

[MMeilicke]

How many miles did you have on the oil when you did the oil analysis?

 

[2Rowdy]

4920 miles on the first analysis. Changed oil and filter.

8133 miles on second analysis. changed oil and filter.

 

[betterthanstock]

Diesel will evaporate from oil when the oil heats up during a long drive.



Biodiesel will gel (polymerize) the oil and cause failure.