Seeing MC perform exceptionally better than RT6.... I'm just done with 5w40 in my truck, never to use it again, after my experience with it foaming, looking like melted milk shake. This confirms to me that RT6 5w40 ain't what it use to be. My next fill is RT5 10w30 Semi..... That oil is super robust and not as many VII's as 5w40.
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