I normally use an AGIP synthetic for my 86 300SDL, recommended by my MB mechanic. The winters are just too cold here in the northeast (Vermont) to use conventional in a diesel. I just moved to the boonies, and the only synthetic I can get around here is Castoil syntec 5W-50, or Mobil 1 10W-30 or 5W-30. Would either of these be OK for a diesel in very cold weather? Thanks,
Jim