Never really checked 5. 9's because with no aftertreatment there was no reason to suspect any fuel was getting past the rings. I still don't understand all the emotion about the oil level rising. If there is less than 5% fuel dilution it is not a problem. And at 5% of 12 quarts, it's about 1/2 quart over the oil change life. So my opinion still is, change the oil per the oil change light, and don't worry about the level. I have yet to see a 5. 9 or 6. 7 that uses any oil between changes, so barring a major leak, the oil level is going to be OK.
Well I'm not sure when you say "all the emotion about the rising oil level" if you are speaking to me, but since I started the thread I am suspecting it is. I don't care about a little bit of fuel slipping by, I agree that a couple percent shouldn't have much noticeable effect on the engine, not sure if I agree with Cummins 5%, but I suppose they should know. However, at the end of the day, there is still 3 litres of something ending up in my oil and it is reducing my viscosity to SAE 30wt. That is something to care about. Would you run 30wt in your new truck? I wouldn't. I am waiting on news from Finning's oil labs to hear if they have a way of measuring soot content, if so that is the next step for me as I suspect it may be soot that is raising the oil level and diluting the viscosity of the oil. If it is soot, I can filter it out. If it's something else then I'll cross that bridge when I come to it.
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