Originally Posted by flars
"I beleive that anything into the 40's weight will be fine. Conventional or syn"
True. The stuff-that-is-to-be-feared is NOT used in 40 wt and higher.
Yep...most oils containing energy conserving friction modifiers (or whatevs) are used in x-30 weights and below. This is a big part of the reason almost all new cars these days specify a 5-30 or 5-20 oil -- to cut operating friction and eke out more fuel mileage!