Originally Posted By: Johnny
If you don't need the benefits of the small amount of esters in HM oil for seal conditioning, and all you want to do is bump up the viscosity, the 15W-40 is the ticket and it will save you some money. Any of the major brands will serve you well for your application, even in the Tulsa winters.
I am near OKC but same difference...but I do want the HM oil pack cause of some minor seeps...HM oil seems to keep this under control in my vehicles, but if no leaks I might consider an HDEO as you are suggesting. Heck they even make Rotella in 10w30 but I am not sure why???