"Shear down the viscosity improver"

[TomsKingRanch]

Got my first Blackstone report on my 07 F350 6.0L King Ranch and everything looks great. The narrative says "This engine model tends to shear down the viscosity improver in an oil, which results in a low vis but this isn't a problem." Can anyone explain what this means? I use Royal Purple 15w-40 and change it every 5K, I know I could go more, but it's my baby! I love the truck and will be still paying for it a while, any thought or comments would be appreciated.

 

[RoyBoy]

6.0's are know to be hard on oil. Oil shear lowers the viscosity of the oil. IIRC, this is mainly from the high pressure oil system that operates the injectors. Using good oil and changing that often you should be fine.