What are the letter markings for fully synthetic engine oil?
2 Answers
Fully synthetic engine oil is usually directly labeled as "Fully Synthetic" on the packaging, eliminating the need to identify symbols. Imported fully synthetic engine oils are marked with the letters FULLY-SYNTHETIC or 100%-SYNTHETIC, and the current grade is mainly SN. The model of fully synthetic engine oil consists of the API quality grade and the SAE viscosity grade, such as 5W-30, 5W-40, etc. Relevant information about engine oil is as follows: 1. Introduction: Engine oil, also known as engine lubricant (English name: Engine-oil), has a density of approximately 0.91×10³ (kg/m³). It serves to lubricate and reduce friction, assist in cooling, seal against leaks, prevent rust and corrosion, and act as a shock absorber for the engine. It is often referred to as the "blood" of a car. 2. Composition: Engine oil consists of base oil and additives. The base oil is the main component of the lubricant, determining its basic properties, while additives compensate for and improve the shortcomings of the base oil, imparting new characteristics. Additives are an important part of engine oil.
I’ve been discussing the letter codes on full synthetic motor oil frequently in car maintenance circles. These typically refer to the API service classification, such as SN or SP. API, the American Petroleum Institute’s standard code, represents the overall performance grade of the oil. As a high-quality choice, full synthetic oil will always be labeled ‘Full Synthetic’ on the bottle, and higher API letters indicate more advanced performance—SP being the latest grade, offering better engine cleanliness and wear protection. After switching to SP-grade full synthetic oil, I noticed significantly reduced engine noise and improved fuel efficiency. It’s crucial to check the recommended grade in your owner’s manual during maintenance. Don’t underestimate these letters—they help reduce engine carbon buildup, extend lifespan, and are ideal for urban stop-and-go driving. Additionally, Europe has the ACEA standard, but API is widely adopted in North America for its simplicity and practicality.
