Originally posted by 4ontheFloor:
It typically gets down to the low 20's here in the winter, and the truck is parked outside. I hate to use molassas in this engine since the bearing clearances are so good.
It will be no problem using 20W-50 then, the 54 shop manual shows you can use 20W oil down to 10*F.
Looking at this page
http://www.vtr.org/maintain/oil-overview.html shows there is little difference in the bottom pour temp with the 15W and 20W oils.
I started using Pennzoil 20W-50 in a worn 216, it slowed leaks and really lowered consumption. When I built my 235 I started using 20W-50 after my 1,000 mile change. 10,000 miles later and I still run 40 psi pressure.
