Butch Davis wrote:

Jeff,

No argument. Consider, however, that the engine is lubricated by 10W40
weight oil. When cold the oil is 10W (mas o menos) and loose rod bearings
would not hold pressure well if at all. When the engine is at operating
temperature the lubricating oil is 40W or so. It's difficult for me to
visualize an engine with 10W at idle cold having pressure much higher than
the same engine with 40W hot at 3800 RPM.


10W-40 weight oil is not more viscous at temp than when cold.
It's less. What multi-weight oils do is thin less with temp.
So, 10W-40 is (theoretically) as thin as 10W is when 10W is cold
and, when hot, it's as thick as 40W is when 40W is hot. That's
still thinner than 10W cold, but not as thin as 10W hot.

-Raf

--
Misifus-
Rafael Seibert

http://www.ralphandsue.com