Mobil 1 Synthetic 5W30 Motor Oilstar rating 4martin langleyMarch 1, 2010once i went synthetic i thought it was all talk but this stuff really works. i have a 2001 expedition with 175,000 miles and i started using mobile 1 when i lived out in the hot sands of vegas. i moved to fla. 3 years ago and i havent stop using it. i have had machanics under the hood like wow your engine runs like a new truck. mobile 1 baby it doesnt get any better.