Myths About Synthetic Oil
In an effort to set the record straight,
we've assembled here ten of the more persistent myths
about synthetic motor oils to see how they stack up
against the facts.
Synthetic motor oils damage seals.
Untrue. It would be
foolhardy for lubricant manufacturers to
build a product that is incompatible with
seals. The composition of seals presents
problems that both petroleum oils and
synthetics must overcome. Made from
elastomers, seals are inherently difficult
Ultimately it is the
additive mix in oil that counts. Additives
to control seal swell, shrinkage and
hardening are required, whether it be a
synthetic or petroleum product that is being
Synthetics are too thin to stay in the
Untrue. In order for a
lubricant to be classified in any SAE grade
(10W-30, 10W-40, etc.) it has to meet
certain guidelines with regard to viscosity
For example, it makes no difference whether it's 10W-40 petroleum or
10W-40 synthetic, at -25 degrees centigrade
(-13F) and 100 degrees centigrade (212
degrees F) the oil has to maintain a
standardized viscosity or it can't be rated
Synthetics cause cars to use more oil.
Synthetic motor oils are intended for use in
is, engines that don't leak. In such
engines, oil consumption will actually be
reduced. First, because of the lower
volatility of synlubes. Second, because of
the better sealing characteristics between
piston rings and cylinder walls. And
finally, because of the superior oxidation
stability (i.e. resistance of synthetics
against reacting with oxygen at high
Synthetic lubricants are not compatible with
synthesized hydrocarbons, polyalphaolefins,
diesters and other materials that form the
base stocks of high-quality name brand
synthetics are fully compatible with
petroleum oils. In the old days, some
companies used ingredients that were not
compatible, causing quality synlubes to
suffer a bum rap. Fortunately, those days
are long gone.
something to keep in mind, however, whether
using petroleum oils or synthetics. It is
usually best to use the same oil for topping
off that you have been running in the
engine. That is, it is preferable to not mix
your oils, even if it is Valvoline or Quaker
State you are using. The reason is this: the
functions of additives blended for specific
characteristics can be offset when oils with
different additive packages are put
together. For optimal performance, it is
better to use the same oil throughout.
Synthetic lubricants are not readily
This may have been the case two decades ago
when AMSOIL and Mobil 1 were the only real
choices, but today nearly every major oil
company has added a synthetic product to
their lines. This in itself is a testament
to the value synthetics offer.
Synthetic lubricants produce sludge.
In point of fact, synthetic motor oils are more sludge resistant
than their petroleum counterparts, resisting the effects of high
temperature and oxidation. In the presence of high temperatures, two
things can happen. First, an oil's lighter ingredients boil off,
making the oil thicker. Second, many of the complex chemicals found
naturally in petroleum base stocks begin to react with each other,
forming sludge, gum and varnish. One result is a loss of fluidity at
low temperatures, slowing the timely flow of oil to the engine for
vital component protection.
Further negative effects of
thickened oil include the restriction of oil flow into critical
areas, greater wear and loss of fuel economy.
their higher flash points, and their ability to withstand
evaporation loss and oxidation, synthetics are much more resistant
to sludge development.
Two other causes of sludge -- ingested
dirt and water dilution -- can be a problem in any kind of oil,
whether petroleum or synthetic. These are problems with the air
filtration system and the cooling system respectively, not the oil.
Synthetics can't be used with catalytic
converters or oxygen sensors.
There is no difference between synthetic and
petroleum oils in regards to these
components. Both synthetic and petroleum
motor oils are similar compounds and neither
is damaging to catalytic converters or
oxygen sensors. In fact, because engines
tend to run cleaner with synthetics, sensors
and emission control systems run more
efficiently and with less contamination.
Myth#8: Synthetics void warranties.
Untrue. Major engine
manufacturers specifically recommend the use of synthetic lubricants. In
point of fact, increasing numbers of high performance
arriving on showroom floors with synthetic motor oils as factory fill.
New vehicle warranties are based upon the use of oils meeting specific
API Service Classifications (for example, SJ/CF). Synthetic lubricants
which meet current API Service requirements are perfectly suited for use
in any vehicle without affecting the validity of the new car warranty.
In point of fact, in the twenty-eight years that AMSOIL Synthetic
Lubricants have been used in extended service situations, over billions of
miles of actual driving, these oils have not been faulted once for voiding
an automaker's warranty.
Myth #9: Synthetics last forever.
Untrue. Although some experts
feel that synthetic base stocks themselves can be used forever, it is well
known that eventually the additives will falter and cause the oil to
require changing. Moisture, fuel dilution, and the by-products of
combustion (acids and soot) tend to use up additives in an oil, allowing
degradation to occur.
However, by "topping off", additives can be
replenished. Through good filtration and periodic oil analysis, synthetic
engine oils protect an engine for lengths of time far beyond the
capability of non-synthetics.
Myth #10: Synthetics are too
Untrue. Tests and experience have proven that synthetics
can greatly extend drain intervals, provide better fuel economy, reduce
engine wear and enable vehicles to operate with greater reliability. This
more than offsets initial price differences. All these elements combine to
make synthetic engine oils more economical than conventional
In Europe, synthetics have enjoyed increasing
car buyers look first to performance and long term
value rather than initial price. As more sophisticated technology places
greater demands on today's motor oils, we will no doubt see an increasing
re-evaluation of oil buying habits in this country as well.