I, too thought the large spread between the numbers on oil was not desirable. Maybe that is only for petroleum-based oils. The way it was explained to me is that the 0w lets the oil flow immediately especially when the engine is cold. Then, it thickens up under heat to the 40. I guess I will go with it. I notice that many manufacturers are recommending 5w30 and 0w30, etc. Hopefully this thread will get some more comments and discussion going. Us Benz guys will argue and discuss oil until we die I guess.

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2000 E430 Sport (European Delivery)
Brilliant Silver/Ash Leather
Brabus Leather/Wood Sport Steering Wheel
PowerChip
Euro Front Bumper Strips, Debadged
E55 "Carbon Fiber" Door Pillar Trim
E55 Tail lights
E55 AMG/Bilstein Shocks
Eibach Springs, #1 Pads
H & R Sway Bars
Speed Yellow Calipers
18" x 8" SSR Integral Wheels
245/40ZR 18 Bridgestone Potenza RE960AS Tires

1986 Porsche 944 Turbo
88K miles