grober
MB Master
As long as it meets MB approval for your engine a 10w40 will be fine. It will make starting at very cold temperatures slightly harder.
Mercedes-Benz Specifications for Operating Fluids: Engine Oil, Gear Oil, ATF, Coolant, Brakefluid
Mercedes-Benz Specifications for Operating Fluids: Engine Oil, Gear Oil, ATF, Coolant, Brakefluid