Automotive engine oils are mainly divided into 10 types. Mineral oil has a lower cost but weaker oxidation resistance, making it suitable for low-emission economy vehicles, and It is best to replace it every 5,000 kilometres or 6 months. Semi-synthetic oil offers good overall performance, making it suitable for family cars with naturally aspirated engines, with a replacement interval of approximately 7,500 kilometres. Fully synthetic oil provides excellent high- and low-temperature performance and oxidation resistance, making it ideal for turbocharged or high-performance engines, with a replacement interval that can exceed 10,000 kilometres. For viscosity grades, there are high-temperature engine oils such as SAE 20-50; the larger the number, the higher the high-temperature viscosity, making them suitable for high-load engines. Low-temperature engine oils such as SAE 0W-25W; the smaller the number before the W, the better the low-temperature fluidity, making them suitable for cold regions. All-weather engine oils such as 5W-30 and 10W-40 can adapt to various temperature environments. Additionally, there are petrol engine oils (such as SN grade) and diesel engine oils (such as CI-4 grade) classified by API quality grades, as well as summer engine oils and winter engine oils categorized by season. When selecting engine oil, factors such as engine type, operating environment, and manufacturer recommendations should be considered. Turbocharged models are recommended to use fully synthetic oil, while ordinary naturally aspirated engines may opt for semi-synthetic or mineral oil. For instance, in tropical regions, engine oils with higher high-temperature viscosity can be selected.
