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Speed and load also affect
oil consumption. e higher the
revolutions per minute, the more
oil will be consumed. e added
pressure on the seals and gaskets
allows some of the oil to find its
way around and get burned away
in the combustion chamber.
In addition, the condition of
the seals and gaskets should be
considered. e older and more
worn the seals are, the more oil
will be consumed.
High operating temperatures
can also impact oil consumption.
e hotter the engine runs, the
lower the viscosity will be. Once
again, it will be easier for a thin oil
to reach the combustion chamber
and get mixed and burned with
the fuel. Keep in mind that there
is a point at which the oil's smaller
molecules will evaporate. If the oil
being used has a viscosity that is
below the recommendation of the
engine manufacturer, oil consump-
tion will occur for the same reason.
High volatilit y is another
factor in oil consumption. Usually
found with lower quality base oils,
the volatility is the evaporation
of smaller oil molecules. This
oil vapor reaches the crankcase
headspace and is often pulled into
the intake and consumed by the
combustion process.
So, what could cause a sharp
decline in oil consumption? With
so many variables, it can be difficult
to pinpoint a single offender. It may
be just the right combination of a
few factors. e most likely causes
are simple things like a viscosity
change, a lubricant quality change,
a seal that was once leaking but
has now stopped or operational
severity changes.
ML
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one of
Noria's experts, email it
to editor@noria.com.
ML
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