I recently changed my oil using Royal Purple instead of my usual Rotella T5 Synthetic Blend 10w30. I felt like one of those guys who insists on pumping 93 octane into their 4.0 because it costs more and, therefore, must be better.

I don't feel that way anymore.

My Jeep runs significantly quieter and smoother. At first, I thought it was just my imagination, trying to justify the additional cost of the pretty purple juice but I've had three passengers voluntarily mention how smooth and or quiet my Jeep seems. My uncle, who knows cars, said, "So, you finally bit the bullet and replaced those motor mounts?" Is there something about Royal Purple that would make such a significant difference in refinement?

 

Oil should not make that much of a difference in noise unless you changed viscosity or the old oil needed changed a long time ago.