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How is Oil Viscosity Measured?
How is oil viscosity measured?
-- Miles Biery, Frankfort, IN
Viscosity is now commonly reported in centistokes (cSt), measured at either 40°C or 100°C (ASTM Method D445 - Kinematic Viscosity). The centistokes rating is converted into the SAE weight designation (e.g., SAE 40, SAE 10W-40). See the SAE J300 specifications for more information.