Data point: 100k miles on a buick 3.0l v6, oil&filter changed regularly
at 3k miles using non-synthetic oil. Engine torn down for a rebuild,
virtually no wear on cylinders, bearings, etc. Engine was revved to
redline very frequently, and held at WOT/near WOT, and also subjected
to rapid accel/decel (yes, I've had it on a oval race track, and certain
country road routes that facilitated it) regularly over the 100k.
The tear down occurred after a failed oil pump bypass failure, due to
running 10w30 oil at -20oF; I found out after that happened that doing
so is certain to kill that bypass. Use only 5w30 with extended periods
below 20oF in that motor. I didn't know if there was any internal
damage down when it was run with oil pressure, so we pulled it and
sent it in. The machine shop had to ask why it was sent in.
> -----Original Message-----
> From: Christopher.Albers@bubbs.biola.edu
> ... my agency has
> tried synthetic oils and found it to be more costly without any
> significant improvement in vehicle life.
> ... Modern engines
> last longer not because people use synthetic oil or because they drive
> "normally." It is because the materials from which they are made are
> Considering turbos, I would agree that this would be a case where
> synthetic oils would be superior. Oils are subjected to much higher
> temps and this is where the advantage of synthetic oil can really be
> [Chris Meier] agreed.
> Christopher Albers