Viscosity Test

Used Quaker State ® Passes ASTM D445 (KV 100)

Quaker State Viscosity Test

Viscosity Test, Used Quaker State passes ASTM D445 (KV 100)

The ASTM D445 (KV 100) test measures an oil’s ability to maintain viscosity even at high operating temperatures, a crucial aspect of engine protection. Modern engines use motor oil as a hydraulic fluid and depend on motor oil viscosity to help “float” metal surfaces away from each other on a “hydrodynamic wedge”—a thin film of motor oil that keeps metal parts separated and engines functioning properly. Maintaining viscosity means an oil stays in grade and does not thin out prematurely, which could lead to metal-to-metal contact. “KV” refers to Kinematic Viscosity, the “100” refers to the Celsius temperature at which the viscosity of the oil is measured. And the used Quaker State® SAE 5W-30 that was tested after thousands of miles in New York City taxis was so durable that it still met the KV 100 standard for brand-new oil, which means it still retained critical engine protection at high temperatures, still functioned as an SAE 5W-30 oil, and still maintained a critical film of oil on engine parts to prevent metal-to-metal contact inside your engine — even when it was ready to be replaced. (By the way, in multi-grade oils, the higher number always refers to its viscosity at higher operating temperatures, the lower number to its viscosity at lower operating temperatures or startups. So in the case of an SAE 5W-30, the KV 100 test would determine its ability to function as a 30-weight at higher operating temperatures. And it’s easy to remember which number is which; the “W” next to the lower number stands for “Winter.”)


Quaker State Motor Oil