Re: Will the wrong oil weight cause damage?
Engines are built with certain clearances and the wight of the oil need to conform to those clearances. Oil acts like little ball bearings between the surfaces. As an engine get older these clearances start to increase and so you can extend the life of your engines by increasing the weigth. My engine has 61,000 miles on it and loves the 5w 40 Mobil One. 5w works great in cold weather, so since MB reccomends 0w I am assuming these engines are built with very tight clearances. If my engine still only had 7,000 miles I would still be using the 0w.