What does synthetic oil 5w30 mean?

[VonJustin]

Synthetic oil 5w30 means: The freezing point temperature corresponding to 5w oil is minus 30 degrees Celsius. The number after w is 30, which refers to the viscosity at 100 degrees. The larger the number, the higher the viscosity of the oil and the stronger its ability to withstand high temperatures. The viscosity of the oil indicates whether the oil is thin or thick. Low viscosity means it is thinner, with less resistance to relative movement under external forces; high viscosity means it is thicker, with greater movement resistance but better lubrication effects. Oil, also known as engine lubricant, serves to lubricate and reduce wear in the engine, assist in cooling, seal against leaks, prevent rust and corrosion, and act as a shock absorber. Oil consists of two parts: base oil and additives. The base oil is the main component of lubricating oil, determining its basic properties, while the additives compensate for and improve the shortcomings of the base oil, making them an important part of lubricating oil.