Originally Posted By: dave1251
I know of someone using Mobil Delvac in his Infiniti G37. I wonder if this tailor will chime in on this thread?
I wouldn't hesitate to use T6 in my G37. The ZDDP in Delvac 1 and Rotella isn't ridiculously high by any stretch of the imagination, and certainly not out of line with any of the Euro oils, such as M1 0w-40. As you pointed out, it's not out of line with what was potentially available when the vehicle was new.
Rotella T6, M1 0w-40, M1 10w-30, PYB 5w-30, and so forth all would be perfectly fine. The vehicle is long out of warranty. Don't ignore the manual's recommendations completely, but purchase by cost, availability, convenience, and even OCI. Up here, I don't like the "regular" price of Mobil 1, and I wouldn't be buying a synthetic 10w-30, as CATERHAM pointed out, so M1 10w-30 would be near the bottom of my list of choices. In California, that would be another matter altogether, particularly with respect to price and climate.
jbl_91762: Do what works for you. As ARCO points out, if you try it and don't like it, you can always try something else. I wouldn't worry about using dual rated HDEOs in gasoline engines (where the viscosity is at least somewhat reasonable and the choice is made appropriate to the weather) after warranty. T6 has a high initial TBN and good retention, so you may be able to get some advantage from that over an ordinary PCMO.