Many users believe that lubricants with darker colors have higher viscosity, or that oils that feel more sticky when touched by hand have higher viscosity. Some users even believe that the viscosity of drawing oil is higher, but these judgments are unscientific. Some users also subjectively judge the viscosity of the used engine oil based on the state of the waste oil after use. For example, some drivers have reported that when changing the oil, if the waste oil is released

The engine oil is released when the car is hot because the viscosity of the lubricating oil decreases with the increase of temperature, and the fuel that enters the oil tank due to engine wear dilutes the engine oil. In addition, using multi-stage oil will become thinner after shearing, which is a normal phenomenon. Therefore, there is no scientific basis for judging the selected oil thinness.

Therefore, the viscosity of lubricating oil can only be determined by measuring it with a viscosity meter.