I always assumed that even 100% synthetic oils came from petroleum feedstocks. Are you sure that Amsoil 3000 isn't petroleum-based? I don't mean to be argumentative, but am just hoping to learn.

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1968 220D, w115, /8, OM615, Automatic transmission.
My 1987 300TD wagon was sold and my 2003 W210 E320 wagon was totaled (sheds tear).