What is the difference between fully synthetic and semi-synthetic engine oil?
2 Answers
Engine oil, also known as motor lubricant, differs between fully synthetic and semi-synthetic types in the following ways: Different base oils: Fully synthetic engine oil is made from a blend of Group III, IV, and V base oils; semi-synthetic engine oil uses Group III base oil. Different replacement intervals: Fully synthetic engine oil should be replaced once a year or every 10,000 km; semi-synthetic engine oil should be replaced every six months or every 7,500 km. The functions of engine oil include: Cooling and temperature reduction; sealing and leak prevention; cleaning and purification; shock absorption and buffering; lubrication to reduce wear; rust and corrosion prevention; component protection, etc.
As a car enthusiast who cherishes my vehicle like my own life, I've used both full synthetic and semi-synthetic oils multiple times. Full synthetic oil is entirely chemically synthesized, with high-purity base oil and excellent low-temperature fluidity. It makes winter engine starts as smooth as new, effectively cleans internal carbon deposits, and reduces component wear. With strong oxidation resistance, it doesn't break down easily under high temperatures, making it ideal for long-distance trips or aggressive driving. Even at high engine temperatures, it remains stable, often lasting over 10,000 kilometers before needing replacement. Semi-synthetic oil is a blend of mineral and synthetic oils, more affordable but with inferior low-temperature performance and durability, typically requiring changes every 7,500 kilometers and offering weaker cleaning capabilities. For enthusiasts seeking ultimate performance and protection, full synthetic is worth the investment; for daily commuting, semi-synthetic is cost-effective and sufficient.
