Whereas
lubricant additives include such
compounds as methyl silicones
and dimethyl silicones as an
antifoaming agent, the
concentration of antifoam is
typically below 1 part per
million (PPM). As such,
other sources of silicon should
be considered when assessing the
intergrity and quality of new
oil.
One of the
most common and concerning
sources of silicon in a
lubricant (either new or used)
is abrasive contamination
introduced to the lubricant from
the environment. Silicon from
this sources is commonly
abrasive in nature. In the case
of used engine oil, the level of
silicon typically considered
high enough to necessitate an
oil change is 20ppm. A
concentration of 7ppm silicon in
a new oil usually requires
attention.
It is
important to note that
contamination can be introduced
to a lubricant at a number of
stages in the blending process.
In addition, contamination can
also occur in the packaging and
transportation of lubricants.
For details on ASTM D5185 test
method click here. |