That means these engines usually need lower-viscosity oil—oil that is “thinner” and flows more easily to form a cushion of lubrication between two parts. At lower viscosity, synthetic oil ...

“An old axiom in the lubricants business is to use the ... frequent jackrabbit starts and hard stops.” [VIDEO] Why an Oil's Viscosity Index is Important Measuring fuel efficiency gains in ...

but the oil must have enough viscosity to provide the needed oil film thickness for adequate lubrication and machine durability. During operation, the oil film varies throughout the engine.

Which lubricant should you use in your vehicle ... “the better oil, like a synthetic oil, the VI (viscosity index) will be higher – [meaning] the viscosity changes less with temperature ...