W Viscosity affects flow well above freezing too. 75F is what, maybe 24C? in that area anyway. In engine terms that certainly cool. Thinner "W" will flow into smaller tighter machined tolerances better, not just flow better in freezing temps.
So yea, use 5W/40.
Rotella T-6 is the real deal. I use it vett's bikes, UTV's, my deere, the cars, everything. Hard to beat at any price, and a great value yo can get almost anywhere.
Last edited by dafish; 11/15/19 06:26 PM.