wrote:
I'm really not sure if the synthetic oil has to contribute to the
quietness of the engine.

maybe so.

I've always been leary of using a synthetic, because I don't have new
engines for one. and I've known of people to change to synthetic on
older vehicles with 90+ thousand miles, then complain because the
bearings are hammered out of the engine. I've always copnsidered that
the reason why is because with bearings with high milage already
"broken in" that they have an excess clearence in the tolorances, which
is fine with a 10 and even 5W motor oil, but when you throw in
synthetic, which initially is thinner than ATF, or water, the viscosity
isn't really changed with heat, but there is less oil pressure because
of the tolorances being opened up so the oil pressure drops.

Thats my view.


This is from a website called Motor Oil Myths and Facts here is the
URL:

http://www.nordicgroup.us/oil.htm

One of the myths:

Thicker is Better Myth
The reason that oil viscosities have gotten thinner is because bearing
clearances have become smaller. Using thicker oils will interfere with
oil flow and the oil pressure will increase. In a worn engine it may be
okay to increase the viscosity of the oil because the bearing
clearances have become larger.

Anyway, pretty good site!