SL in oil refers to a specific Service Level designation for motor oil, as defined by the American Petroleum Institute (API). It indicates a prior generation of motor oil standards.
Understanding API Service Levels
The API develops performance standards for motor oils. These standards ensure that oils meet the requirements of various engines. Each level is designed to meet the needs of different engine technologies. SL is an older standard, which has been superseded by newer ones.
SL vs SN: Key Differences
The reference explains that:
- SL stands for "Service Level" and is a prior generation of motor oil standards.
- SN stands for "Service Level N" and is a more recent motor oil standard that succeeded "SL".
The progression from SL to SN reflects advancements in engine design and performance requirements. SN-rated oils offer better protection and performance compared to SL-rated oils. It is generally recommended to use the API standard specified by the vehicle manufacturer.
Table of API Service Levels (Simplified)
| API Service Level | Relative Age | Improvement Over Prior Level |
|---|---|---|
| SL | Older | Good performance at the time |
| SN | Newer | Better protection and performance |
Note: This table does not represent the entirety of API Service Levels, but is to help show the relationship between SL and SN.
Key Takeaways
- SL is an older standard and may not provide the same level of protection as more recent standards.
- Always check your vehicle's manual for the recommended API service level for your engine.
- Using a more advanced oil, like SN, instead of an older standard, is usually safe and beneficial, assuming it meets the vehicle manufacturer's specifications.
