Well, I have about 100 miles on my "hesitant" fill of Mobil 1, and it seems to be running great. There is LESS noise with mobil 1, even at startup after my car sat in my cold garage with overnight lows of 2 degrees F. for a couple days. And I can tell, it's already turning black! When I first put it in, I couldn't even see any on the dipstick. Now it looks like what dino would look like after 1,000 miles in my car . Cleaning I'm just happy I'm not getting excessive noise. Over all, it seems to be running better; less vibration, better power, better fuel economy. This is 10w-30 Mobil 1. Oh, I also left a bottle outside when it was 2 degrees outside with a windchill of about 20 below, and it was much less viscous then 5w-30 Pennzoil High Mileage. Hopefully I won'y get gradual engine knock with it like I did with my Grand Am on Mobil 1. No more of this 3,000 mile oil change crap!