When Ford used a pump that had its own oil sump the owners manual wanted the oil changed every 50 hours! I doubt many did get serviced that often but that is what was recomended because of the small leakage from the delivery valves diluting the oil.
My $.02 Don

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Red Green "This is only temporary,Unless it works!"

97 E300D 157000 miles
87 300TD ?141k? miles