I have a 2003 Ford Ranger 4x4 pickup. 4.0 Lt Engine. I want to use a synthetic oil for this vehicle and I have narrowed my choices down to Mobil 1 0w40, Cat DEO 5w40 and Schaeffer 7000 15w40 or 10w30. ACEA A3 rating is a must. (I must add that researching this site has been a learning experience when I once thought I knew a lot about synthetics.) My concern is using an oil that will hold up to the abuse of in town stop and go, long idle times (infrequent) dusty roads. My thought after doing research on this site is that the above listed oils may handle my needs. However, I would like to extend the drain intervals to 5k- 7k miles or more if possible. Also, the oils detergent / cleaning ability is important. The diesel oils are appealing. Any long term users of any of these oils have an opinion. From the UOA section, it appears that Mobil 1 0w40 has the tendency to shear down losing viscosity. It's cheap though at $3.77 qt at a local Wal Mart. That's the regular price. Cat DEO / Delvac 1 shows good numbers and I found a local CAT dealer who will order it for $19 Gallon. Is it too thick for my application though? Last, Schaeffer S7000 I read that it is a great oil for a blend and it has shown good UOA numbers. Is the S7000 15w40 too thick? Is the 10w30 enough of an oil the extended drain? Any opinions are welcomed.