Originally posted by rjnonnie
I use to switch to Mobil 1 15W-50 during the summer months but this year I decided to stick with 0W-40. 0W-40 is rated for year round use with the "newer" (112) Mercedes engines because of the tight tollerences.
Well, nothing wrong with 0W 40 in the winter, that's what my dealer uses/recommends for winter driving.
I would be very hesitant to use it on extended trips, or high speed driving in the summer.