If I recall correctly, I've read that the 5%-10% biodiesel added to most diesel fuels adds sufficient lubricity to protect the injection pumps, at least on the older models (eg, the 617.92_ series). In these engines, my understanding is that the upper injection pump relies on fuel for lubrication, and the lower part of the pump utilizes engine oil.

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Marshall Welch
Seattle, WA
1982 300D-T