[DrJfrmLA]

The recommended oil for my '04 W220 is Mobil 1 0W40. You don't say what year or model you own, but I assume it's the same for all W220s. My indie recommended 5W30, but the owner's manual says 0W40 so that's what I use. Everybody thinks they are a petroleum engineer when oil weights are discussed. If the manufacturer was indifferent, I suppose there would be a range of viscosities recommended. Since there aren't, I'll use what the engineers in Stuttgart say. Synthetic oils have different lubricating properties than petroleum lubricants, so I'm not sure the viscosity numbers are precisely equivalent anyway.