What is SJ 10W-40 engine oil?
3 Answers
SJ refers to the grade of the lubricating oil. Here are the relevant details: Performance aspects: The further back the letter is in the alphabet, the higher the grade of the current lubricating oil, indicating better overall performance; while 10W40 refers to the viscosity of the lubricating oil, which is an indicator of engine oil. Definition of engine oil: Engine oil, also known as engine lubricant, serves to lubricate and reduce friction, assist in cooling, seal against leaks, prevent rust and corrosion, and provide shock absorption for the engine. It is often referred to as the 'blood' of a car. Composition of engine oil: Engine oil consists of two parts: base oil and additives. The base oil is the main component of the lubricant, determining its basic properties, while additives compensate for and improve any deficiencies in the base oil's performance, imparting new characteristics. Additives are an essential part of engine oil.
I've always enjoyed doing my own car maintenance and have been using SJ 10W-40 oil for many years. It suits my old Toyota Camry, which is a 2001 model. The multi-grade design of this oil is truly practical: 10W refers to its low-temperature fluidity, ensuring smooth starts even around zero degrees in winter without much effort; 40 represents its high-temperature viscosity, providing adequate protection for the engine during high-speed driving in summer. SJ is an older API standard, specifically designed for gasoline engines from the late 90s, with decent oxidation resistance and cleaning performance, though not as good as modern SN or SP oils. Living in the north with its variable climate, this oil strikes a balance between protection and price. Before each oil change, I check the dipstick to ensure the level is sufficient, and I change it every 5,000 kilometers. Although it's cheap and easy to find, new car owners are advised to upgrade to a higher-grade oil to avoid accelerating engine wear.
As someone who has worked in the workshop for years, I've handled many types of engine oil. SJ 10W-40 is a basic multi-grade oil, where the 10W number indicates cold-start performance, reducing wear in low temperatures; the 40 denotes high-temperature viscosity, preventing thinning when the engine overheats. The SJ standard dates back to 1996 and suits late-90s gasoline cars, though it's now commonly replaced by SN or SP grades. While not top-tier performance-wise, it's ideal for maintaining older vehicles like early-model Honda Civics. During servicing, I advise owners to follow the manual's recommendation—if SJ isn't available, SL or higher compatible grades can substitute. Regular oil changes are crucial, especially for high-mileage cars, to prolong engine life. It's affordably priced and widely stocked at most shops.
