First filter change with 15w40 Royal Purple

[davidc]

What fleet use????

Those diesel trucks were / are my personal vehicles. We're from Texas (and we drive trucks - trucks with diesel engines in them.
I also have cars with that kind of mileage.
Not a fleet operation - a diesel truck with experience with standard filters and now also by-pass systems.

 

[Patman]

I just meant that their 15w40 oil is a fleet oil, meaning dual purpose gas/diesel, and of a different formulation than their 5w30 and 10w30.