Why is Shell 5W30 SL grade?
2 Answers
Reasons why Shell 5W30 is SL grade: This engine oil contains higher levels of phosphorus and sulfur, providing better anti-wear performance. Meaning of SL: The 'S' stands for gasoline engine oil, and 'L' represents the oil grade. In alphabetical order, the further the second letter is in the sequence, the higher the quality, offering better protection for the engine. For example, SL grade engine oil performs better than SJ, SH, or SG grades. Meaning of 5W30: 5W30 - 'W' stands for winter, '5W' indicates it can be used at temperatures as low as -25 degrees Celsius, and '30' represents its viscosity at 100 degrees Celsius is 30.
Shell's 5W-30 oil is labeled as SL grade because it meets the API (American Petroleum Institute) SL service quality standard, which primarily targets engine designs for vehicles manufactured before 2004. The formulation of SL-grade oil focuses on anti-wear performance and oxidation stability, effectively protecting older engine components from excessive wear. Many owners of older vehicles still use this oil because it is specifically designed to be compatible with older catalytic converters, unlike newer standards such as SN, which may affect emission systems. Additionally, as a brand, Shell may retain SL-grade options in its product line to meet the needs of different user groups, such as those driving cars from the 1990s or early 2000s. If your maintenance manual recommends SL-grade oil, choosing this product is appropriate—it helps extend engine life while being relatively affordable, eliminating the need to upgrade to higher standards unnecessarily.
