Synthetic Oil Myths
Synthetic oils have
been available for almost 30 years and a number
of inaccurate myths have developed during this
time. Some areas of misunderstanding are
clarified below, including manufacturer
requirements for using synthetics, how to switch
from conventional to synthetic oil and the
effects of synthetics on an engine.
1: Synthetic oils are too thin to stay in the
This is not true. In order for a lubricant to be
classified in any SAE grade (10W-30, 10W-40,
etc.), it has to meet the viscosity guidelines,
or thickness, specified by the vehicle
Synthetic oils will void manufacturers’
Synthetic oils will not void manufacturer
warranties. They are formulated with the
requirements of the auto manufacturers in mind,
and so if they’re used in accordance with the
owner’s manual, synthetic oils will not void any
of the warranties. The only exception is that
full synthetic oils should not be used in Mazda
rotary engines, which have unique and specific
lubrication requirements. Always check the
vehicle owner’s manual.
Myth 3: You
can’t switch between conventional oil and
Switching between synthetic and conventional oil
will not cause any harm to engines. Synthetic
oils and conventional oils are formulated to
help protect your emission system, including
oxygen sensors and catalytic converters.
4: Synthetic oil will make seals leak.
If an older engine’s seals do not leak with
conventional oil, they will not leak after
switching to synthetic oil. Synthetic oils do
not damage engine seals in an engine of any age.
Synthetic oil cannot be used to “break in” a
In a rebuilt engine, a certain amount of
controlled wear can be expected to occur to
allow piston rings to “seat” and the engine to
“break in.” Synthetic oil may be used for the
“break-in” period and throughout the life of the
Synthetic base oils combined with a strong
additive package allow synthetic oils to perform
better than conventional motor oils under
virtually all conditions.