Fwd: Re: [Vwdiesel] about that oil - again

[Dana Morphew]

Viscosity improvers aren't good lubricators.  They replace oil molecules and are
used to attain the "viscosity spread" in a multi-viscosity oil, so a "big
spread" oil like 10w40 (one of the worst offenders) has more viscosity improving
molecules and less lubricating molecules than a 15w40 oil.   There are good
additives as well...things like anti-oxidants, anti-wear agents (zinc), soot
dispersants, and base number improvers.

-Dana-


>     * The "spread" between the low and high numbers is achieved by
> additives... generally, the bigger the spread, the higher the additive
> content, which is (generally) to be avoided.