Oil Viscosity Classification You Should Know

Viscosity is the measure of a fluid's resistance to flow. How quickly or slowly motor oil flows affects how well it protects your engine.

SAE indicates the oil viscosity grade.

VISCOSITY - is a property of the fluid that determines how fluid the oil is. The higher the viscosity, the thicker the liquid (the lower its fluidity, the higher the viscosity). The lower the viscosity of the oil, the more fluid it will be when starting the engine in cold temperatures.

The viscosity index is a measure of how an oil's viscosity changes with temperature. Oil with a high viscosity index has better fluidity at low temperatures and higher viscosity at a running engine.

Winter oils: SAE 0W, 5W, 10W, 15W, 20W, 25W - Identified by number and letter "W".

Summer oils: SAE 20, 30, 40, 50, 60 - Number only.

Universal oils: SAE 0W-20, 0W-30, 0W-40, 0W-50, 0W-60, 5W-20, 5W-30, 5W-40, 5W-50, 5W-60, 10W-20, 10W-30. 10W-40, 10W-50, 10W-60, 15W-30, 15W-40, 15W-50, 15W-60, 20W-30, 20W-40, 20W-50, 20W-60. The designation is a combination of winter and summer series, separated by dashes.

In cold winter conditions, engine oil must be fluid enough to start the vehicle easily and safely. The heated oil should be thick enough to protect against premature wear.