Full-flow oil filters clean nearly all oil leaving the pump. Bypass filters sample a smaller flow and polish finer particles — a configuration used on some Volvo D11–D13 and related Mack platforms.
Examples: 23151592 (standard) and 23658092 (long-life). This is the primary engine protection filter.
Example: 21707132. It is not a substitute for the full-flow filter; it works with it.
Replace both when the OEM interval calls for a full oil service. Verify the required parts for your engine before ordering.
If your engine is designed for two-stage filtration, skipping bypass filtration can increase soot and fine-particle load over long drains. Follow the OEM service design.
Not always. Long-life elements such as 23658092 are built for extended drains. Use the media type your oil drain interval requires.
