Food for thought:
A forum member, I forget what forum, called Motori to discuss the Eco and oils.
Motori told him to stop using USA oils and to use any Synthetic European oil, 5W-40, meeting MS-12991.
I should have saved what Motori said about the benefits to the Eco when using European oil, it was impressive.
The forum member took Moritori's advice and reported all that Motori said is true.
I'm ready for a change so, like Tom, I ordered Quaker State Euro Full Synthetic 5W-40 Motor Oil, 5-Quart, 22.97 Walmart & Amazon. Why QS, it was the cheapest and meets MS-12991.
I searched for the member's report but could not find it. If I run across it I will post it here.