It must be said that the LF3970’s “500 hours” rating isn’t just some random marketing claim. It’s tied to official maintenance recommendations from Cummins and Fleetguard. In the Cummins ISB6.7 and QSB engine manuals, the LF3970 is listed as offering extended oil drain intervals when used with a premium oil that meets CES (Cummins Engineering Standard). That’s the baseline: If your oi... https://joz-engine.com/can-the-lf3970-really-last-500-hours-between-oil-changes-or-is-that-just-marketing/