Over the past ten years I tried all the oil additives and settled with pure 20W-50 for the past two years until I read about the multi-grade oils losing their 'magic' after 1500 miles.
Switched last summer to straight 30 HD.
I don't even have to go down to 20 for the winter, despite temperatures in the 30s-40s.
Maybe another give-away that my main and rod bearings are in need of replacement?
