Originally Posted By: adamant
i have a few gallons of rotella 15-40 from my diesel and i hate to see it wasted. can i use it in my 2001 f 150 6 Cy.?
Yes, you can use it. The 4.2L pushrod V6 won't mind at all. But, I would save it for the spring/summer/fall. Now is not a good time for 15w40.
You can also thin it out a little too. A quart of Marvel Mystery Oil, quart of Rislone, pint of Seafoam, bottle of Zmax..... should easily thin it out to a 30wt. I would think a bottle of Valvoline-Castrol-Mobil1-Honda-Toyota...0w20 would do the same.
Thinning it out a little would reduce stress on the oil pump, and get the oil flowing through the engine a little quicker.
So, definitely use the 15w40. 1 gallon of 15w40 to a bottle of any of the above 'thinners' will do fine.