What are the different grades of motor oil?
2 Answers
Common motor oil grades include 5W-30, 10W-30, 10W-40, 15W-40, and 20W-50. Here is relevant information about motor oil: Motor oil viscosity grades: Divided into two viscosity grades: Low-temperature viscosity grade and high-temperature viscosity grade. Effects of motor oil viscosity: SAE lubricant viscosity grades are: 20, 30, 40, 50. The higher the number, the greater the viscosity. Viscosity can adjust within a certain range, becoming thicker when hot and thinner when cold, which helps reduce engine resistance and wear.
I've run an auto repair shop for twenty years, frequently helping car owners choose the right engine oil viscosity grade. The key is understanding SAE viscosity ratings: The first number like 0W or 5W indicates cold-weather flow performance - lower numbers mean quicker cold starts. The ending number like 20 or 40 represents high-temperature thickness - higher numbers offer better engine protection. Synthetic oils come in full and semi-synthetic varieties, offering superior durability at higher cost, while mineral oils are budget-friendly for older vehicles. API standards like SN Plus regulate environmental performance. Climate matters too: Northern winters call for 0W-20, while southern summers warrant 10W-40 for better protection. Using incorrect oil accelerates wear - always follow the owner's manual recommendations to save on repair costs.
