viscosity question

[carco]

Not sure where to post this question and if needed moderators please move to proper forum. New member sent from www.6.2-6.5-dieselpage.com. All my oil analysis show the viscosity @ 100*C to be slightly low, yielding an abnormal status. All same brand and weight of oil. Readings between 11.55 to 11.94 for a 15W40 dino oil, the cut point being 12.50. All other UOA specs are always in line with parameters. Question, is this a problem?? Would this be a problem for an extended drain program? thanks bob......

 

[Pablo]

What kind of oil?

Place your full analysis with miles, times etc in the Used Oil Analysis (Diesel) section.

If you want a professional "read" contact Terry Dyson.

Fuel dilution and shearing come to mind......

 

[carco]

Pablo, thanks for the response. The oil happens to be Pennzoil 15w40LL, the only oil our shop has used for our fleet customers for over 14 years. A Mack midliner ran over 720000 miles w/ oil change intervals of 10000 to 21000 miles. In my rollback, the last 4 changes, the only out of bounds stat has been viscosity. I don't know enough about the cut points and importance to know if somewhat low is bad or just something to be aware of if longer change intervals are used. thanks again. bob.....

 

[Terry]

Carco, for $20 I can take a look at the data and answer your question.

I ran a 6.5 GM diesel hauling a race car and associated parts nationwide and am very familar with the issues these engines face.

One to consider is injection pump efficiency, secondly reducing head temps if in boost most of the time. Good fuel delivery and reducing head temps should take care of the shear issues.

Contact me if needed, see my site supporter info at;

www.bobistheoilguy.com/terry.html