What does fully synthetic engine oil 10w40 mean?
2 Answers
The 'w' in the engine oil grade stands for winter. The number before 'w' indicates the low-temperature fluidity of the oil. The smaller the number, the better the fluidity of the oil. 10w corresponds to an external temperature of -30°C, meaning it is suitable for use above -30°C. 10W indicates that the oil is suitable for starting at temperatures above -25°C. The number after 'w' represents the high-temperature viscosity of the oil, typically referring to the viscosity at 100°C. The larger the number, the better the protective performance at high temperatures. Here is some relevant information: Engine oil introduction: It refers to the lubricant specifically used in internal combustion engines. In addition to lubrication, it also has functions such as cleaning, rust prevention, and cooling. The base oil used in today's engine oils is composed of hydrocarbons, poly-alpha-olefins (PAO), and poly-internal olefins (PIO), all of which are organic compounds consisting only of carbon and hydrogen. Some high-grade engine oils may contain up to 20% esters. Engine: It is the heart of a car. There are many metal surfaces inside the engine that rub against each other during movement. These components move at high speeds, operate in harsh environments, and can reach working temperatures of 400°C to 600°C. Under such severe operating conditions, only qualified lubricating oil can reduce the wear of engine parts and extend their service life.
I've driven many cars and found that fully synthetic 10w40 oil means it's entirely chemically synthesized, unlike semi-synthetic or mineral oils. The numbers 10w40 represent viscosity grades: 10w indicates good winter (Winter) cold-start performance, enabling smooth engine starts at temperatures as low as -25°C, while 40 denotes moderate viscosity at high temperatures of 100°C, effectively protecting engine components from wear. I choose it mainly because fully synthetic oil offers superior fluidity and high oxidation resistance, making it particularly suitable for cold northern regions or frequent short-distance driving. After using this oil, I noticed reduced engine noise, slightly lower fuel consumption, and excellent cleaning performance that minimizes carbon buildup. When selecting oil, always refer to your vehicle manual for recommended viscosity—my older car uses 10w40 and has run tens of thousands of kilometers without issues. A major advantage is extended engine lifespan, so I recommend regular oil changes to maintain stable performance.
