How good is the VI improver used in Shell ROTELLA® T Motor Oil?
We use a proprietary viscosity index (VI) improver formulated for Shell ROTELLA® T. It’s exceptionally good in several areas required for premium diesel engine performance– primarily shear stability and deposit control. The exceptional shear stability of the VI improver helps Shell ROTELLA® T Multigrade maintain its viscosity in service to help provide consistent oil pressure. What can soot do to engines? How can a good oil control it? Soot comes from the combustion of diesel fuel and is a problem because of tougher emission regulations. Less soot goes out the exhaust now, but more goes into the oil due to recirculation of exhaust. Soot can be abrasive. When tiny soot particles combine (or agglomerate), they act something like jeweler’s rouge or lapping compound. Agglomerations of soot between metal parts rubbing against each other can hasten wear. Soot can also prevent antiwear additives from protecting critical parts from damaging wear. Soot also contributes to the sludge sometimes
