What type of oil is recommended for a clk 320?

Answer 1

I use Mobil 1 Synthetic Oil it is recommended for 5K miles but i still change at 3K. I do too but go to 5-8K change interval under normal service conditions . Please be aware that Mobil 1 is a synthetic oil as the base oil is made by polymerization of alpha olefins so the molecular chains are relatively linear and not significantly branched so there are few secondary carbon atoms . Secondary and tertiary carbon atoms are sources of chain scission therefore changing the lubrication properties of the oil . Many other brands of "synthetic" oils are refined from crude oil and simple dehydrowaxed to remove the residual parafin waxy materials so they flow well at low temperatures . They contain much higher levels of branching thus higher levels of secondary and tertiary carbon atoms . At a 3K oil change interval the presence of branching is much less a factor but at extended service life , is a consideration . Oils made from polymerization of alpha olefins typically allow lower viscosity by stopping the polymerization at the desired molecular weight and will generally have much tighter molecular weight distribution than oils refined from crude . Note many race engine engineers specify Mobil 1 . This answer from someone who has no affiliation with ExxonMobil but experience developing synthetic lubricants for non-automotive applications .