have Saturn SC1 w/ 110,000 miles
burning 1 qt/ 1000 miles on dino 5W30.
switched to M1 0W40
(primarily because it was going to be away at college and not get my obsessive maintenance at home like before)
no oil consumption in first 2500 miles on M1!
will report as more miles accumulate.
Ok well I did it. Today I went to part source and bought a case of 0W-40 M1. Yup engine runs nice and smooth plus I get better oil pressure not by much though. The guy at the counter sayed that I'm the first one to by this oil. When I went to him he asked me what I was going to put this in and I told him (happily) my 1990 sunbird In any case I'll just be doing 15,000km oci just to make for the cost. Seeing as how this oil is designed for extended oci this should be no problem, unless someone sayes that I could go more.
Because of its better ACEA and Mercedes test ratings, I like 0W40, especially for vehicles with internals that like a thicker oil or for older vehicles.