What is Fully Synthetic Oil and Semi-Synthetic Oil?

[VanTheo]

Fully synthetic oil is blended using Group III, IV, and V base oils, while semi-synthetic oil uses Group III base oil. The functions of engine oil are: 1. As a lubricant, it reduces friction and wear between moving parts; 2. As a coolant, it absorbs heat generated in the engine combustion chamber and piston crown, cooling the engine and preventing overheating. The differences between fully synthetic and semi-synthetic oils are: 1. Different base oils: Fully synthetic oil is blended from Group III, IV, and V base oils; semi-synthetic oil uses Group III base oil. 2. Different replacement intervals: Fully synthetic oil should be replaced annually or every 10,000 kilometers; semi-synthetic oil should be replaced every six months or 7,500 kilometers.