Don't know why it would run better, but the dipstick indicates "min" and "max", and the Benz engines typically consume more oil when kept at the max level. Keeping the level at the midpoint seems to reduce oil consumption....

Jim

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14 E250 BlueTEC black. 45k miles
95 E320 Cabriolet Emerald green 66k miles
94 E320 Cabriolet Emerald green 152k miles
85 300TD 4 spd man, euro bumpers and lights, 15" Pentas dark blue 274k miles