A little more about OIL...

[Steven Ritchie <sritchie@xxxxxxxxxxxx>]

Previously, I gave my arguments why synthetic 10w30 might possibly be fine
for a BMW in non racing applications.  This is from the Redline site:

=3D=3D=3D=3D=3D=3DCUT FROM REDLINE SITE=3D=3D=3D=3D=3D=3D
Red Line 10W30: Best all-weather viscosity grade for gasoline engines in
cars and light trucks that are driven on the street on a daily basis.
Reduces turbo lag and provides more power and economy while providing
thicker bearing oil films at operating temperature than a petroleum 10W-40.
Best all-round, synthetic oil for stock or slightly modified engines in
high- performance cars that are street-driven. Best choice to replace a
5W-30 or 10W-30, petroleum-based or other-brand synthetic oil if maximum
durability is preferred. Acceptable for engines that are occasionally
operated in extreme cold weather.=20

Red Line 10W40: Best choice for engines that typically run high oil
temperature. Best choice for engines in daily drivers operated in very hot
weather on a regular basis. Best choice for medium and heavy duty gasoline
engines in trucks. Best choice for high-performance engines that see street
as well as frequent racetrack duty. Thicker oil film at operating
temperature than a petro-based 20W-50.=20

Red Line 15W50 & 20W50: The ultimate high-temperature protection in Red
Line engine oils recommended for street use. Good for engines that
regularly run very high oil temperatures. Best for engines that run large
clearances such as air-cooled engines or large-displacement, all-out racing
engines that see occasional street use. Provides 25% more viscosity in
bearings than petroleum 20W-50s. Not recommended for use in cold climates
where temperatures are at or below 10=B0F or -12=B0C. Not recommended for
street use in production engines that see sustained oil temperatures below
225=B0F. Those engines should use Red Line 10W-30 or 10W-40.=20
=3D=3D=3D=3D=3D=3DEND CUT=3D=3D=3D=3D=3D=3D

SO, it would seem that the boys at Redline agree with me.  They clearly
state that 15w50/20w50 "Not recommended for street use in production
engines that see sustained oil temperatures below 225=B0F." =20

Recently Garrick Louie posted a message to the digest that said, "What is
your oil temp?  Mine is around 150-225F depending on engine load and
outside temps.  At around 90 degrees outside with stop and go it gets as
high as 225F."  (He has a E36 M3 BTW)=20

So even a E36 M3 engine rarely reaches the 225F level.

In fact some consumer report article found that there was no difference in
the wear rates in NY city cabs between synthetic and non-synthetic oils.
The number one reason that I've heard people say that the study was flawed
was that cabs generally run all day so they see little cold starting.
Well, if that's the case then it would seem that cold start protection is a
MUCH larger factor in engine wear and that lower viscosity oils would
provide longer engine life overall because of their superior cold=
 performance.

So make up your own mind because no one knows the absolute truth including
me...and the reality is that you'll never have enough data to determine if
15w50 or 10w30 is better. =20

Steve

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