What is the difference between SL and SN motor oil?
2 Answers
The differences between SL and SN motor oil are: 1. Different grades: SL motor oil has a lower grade; SN motor oil has a higher grade. 2. Different phosphorus content: SL motor oil contains no more than 0.1% phosphorus; SN motor oil contains no phosphorus. The functions of motor oil are: 1. To reduce wear between the piston and cylinder, and between the main shaft and bearing bush, providing lubrication; 2. To assist in cooling the engine internally; 3. To clean carbon deposits, sludge, and metal wear particles from engine components; 4. To reduce gas leakage and prevent external pollutants from entering; 5. To cushion and absorb shocks from the piston, piston chips, connecting rod, and crankshaft bearings.
The main difference between SL and SN motor oils lies in their updated specifications. The SL standard, introduced in 2001, focuses on sludge control and wear protection, making it quite suitable for older engine models. However, it falls short in environmental friendliness compared to current standards, tending to produce more emissions. The SN standard, an upgrade post-2010, enhances emission performance by reducing phosphorus content to protect catalytic converters, while also improving fuel economy and turbo engine protection. My advice is: if you drive a new car, always opt for SN oil—it saves fuel and extends engine life. For older cars, SL might still work, but upgrading to SN is recommended to avoid emission issues. Always check the label on the oil bottle during changes to ensure the correct type is used—this can help reduce maintenance costs.
