After reviewing several UOAs here at BITOG from Chevron & Mobil in the 15w-40 DELO flavor and comparing them to other 5w and 10w oils from Chevron, Mobil and Pennzoil, it seems that the only common links I can find are: 1--Phosphorus is much higher in all cases with DELO's 2--Viscosity is thicker (duh!) 3--Calcium is generally somewhat higher. Obviously, 15w-40's won't achieve the GF/3 fuel-efficient rating, but, is that it? Are there base-oil properties that go unmentioned? So many things look similar between "diesel" and "car/truck" oils that it just doesn't make sense NOT to use DELO's to some degree, unless, of course you don't like the thicker oils. Outside of the marketing arms of oil companies, are these the only reasons "diesel" oils aren't "good" for gas engines?