How is engine oil graded?
3 Answers
Engine oil is graded as follows: 1. AB series: for gasoline and light-duty diesel engines; 2. C series: for catalyst-compatible engine oils; 3. E series: for heavy-duty diesel engines. The functions of engine oil are: 1. To reduce friction and high temperatures; 2. To cool and lower temperatures; 3. To clean and remove contaminants; 4. To cushion and absorb shocks; 5. To prevent rust and corrosion. Engine oil, also known as engine lubricant, consists of: 1. Base oil: the main component of lubricating oil, determining its fundamental properties; 2. Additives: to compensate for and improve the shortcomings of the base oil. The effects of using inferior engine oil include: 1. Degrading the quality of the oil and reducing its performance; 2. Damaging the lubrication of precision parts such as fuel pumps and injectors; 3. Decreasing the power output of the generator set; 4. Affecting the combustion efficiency of the engine.
I've been driving for many years and have a good understanding of motor oil grading. Simply put, oil grading mainly follows two standards: one is the SAE viscosity grade, like the common 5W-30. Here, 5W represents low-temperature viscosity - the smaller the number, the smoother the cold starts; 30 represents high-temperature viscosity - the larger the number, the better the protection under high temperatures. The other is API quality grade, such as SP being the latest high-level standard, which is more environmentally friendly and better at cleaning engine carbon deposits than the previous SN grade. I often advise car owners to check their vehicle manuals for oil selection and not to use cheap products blindly - choose higher viscosity like 10W-40 in hot summer areas, and lower viscosity like 0W-20 in cold winter regions. Don't exceed 5,000 kilometers between oil changes to properly protect the engine and reduce wear. Regular oil level checks are also crucial - neglecting this may lead to engine overheating and malfunctions, resulting in troublesome and expensive repairs. Overall, choosing the right grade can extend your vehicle's lifespan.
I spend quite a bit of my free time on cars, and the topic of oil classification is quite interesting. First, the SAE system uses letters and numbers to indicate viscosity, like the 'W' in 5W-30, which stands for 'winter,' meaning good low-temperature fluidity; the '30' represents the viscosity value at 100 degrees Celsius. API classification focuses more on performance, evolving from the earliest SA to the current SP. SP-grade oils incorporate new technologies to handle small particulate pollutants, reducing emissions and better protecting engine components. I've actually tried different oils and found that incorrect viscosity can make the engine noisier or increase fuel consumption. The advantage of multi-grade oils is that they are suitable for all seasons, unlike old single-grade oils that could only be used at specific temperatures. When choosing oil, it's also important to pay attention to the API certification mark on the packaging to ensure quality. Additionally, some cars require specific certifications like the ACEA D-grade European standard, and mismatches can lead to poor lubrication and accelerated wear. Sticking to the right classification can save a lot on repair costs.
