TSO
ASL
XLT
We get asked this question so
often that we have included this
special page dedicated
exclusively to answering the
question.
AMSOIL 0W-30, 5W-30 and
10W-30 synthetic motor oils are
ALL 30 weight oils. The
answer is that ANY one can be
used regardless if your vehicle
owners manual says to use, for
example, a 5W-30. "W" means
winter. In winter weather the 0W
oil will flow like a 0W oil, and
the 5W will flow like a 5W oil
and a 10W will flow like a 10W
oil just until the engine warms
up. In order to understand the
differences one has to first
understand that the numerical
values given to these various
weight oils are strictly
empirical numbers. For
example, 0W does not mean that
the oil has no weight. That is
one of the reasons why we say it
is strictly an empirical number.
In order to determine the
differences between the three
oils one has to look at the
kinematics viscosity of each
lubricant. The kinematics
viscosity is essentially the
amount of time, in centistokes,
that it takes for a specified
volume of the lubricant to flow
through a fixed diameter orifice
at a given temperature.
Let's
compare the kinematics viscosity
of the three AMSOIL lubricants:
AMSOIL 0W-30 is 57.3 cST @ 40
deg. C, & 11.3 cST @ 100 deg. C
AMSOIL 5W-30 is 59.5 cST @ 40
deg. C, & 11.7 cST @ 100 deg. C
AMSOIL 10W-30 is 66.1 cST @ 40
deg. C, & 11.7 cST @ 100 deg. C.
As you can see from the data
above the kinematic viscosities
are extremely close. Therefore,
whether you use the 0W-30, 5W-30
or the 10W-30 is strictly a
matter of choice. With the small
differences in kinematic
viscosity you would be
hard-pressed to detect these
differences on initial engine
start-up without specialized
engine test equipment.
All
three oils are excellent motor
oils and ANY one can be used in
a vehicle which requires either
a 0W-30, 5W-30 or 10W-30 oil as
well as in several other engine
applications including an engine
which recommends a 5W- 20 oil.
AMSOIL Series 2000 0W-30 Severe
Service motor oil is one of the
best synthetic lubricants AMSOIL
manufacturers for gasoline
engine passenger vehicles and
light trucks. The molecular and
chemical technology used to
develop this oil was derived
from AMSOIL's Racing Oil. It is
a 35,000 mile/2-year motor oil.
This is the same oil used by
numerous police vehicles and
severe duty fleets nationwide.
In fact, many national racing
teams use the 0W-30 for the
qualifying event, then they
change to the AMSOIL 20W-50
Racing Oil for the race. The
extra horsepower and friction
reduction from the 0W-30 often
assists a race driver in
attaining a better starting
position. In fact, we know
exactly which race teams use it,
but cannot disclose that
information.
This leads to the next topic:
many people also ask us if the
0W-30 is too thin a viscosity
oil for high ambient temperature
operation. The answer is
absolutely not! Thicker
viscosity oils are not always
necessarily better since in
addition to its' various engine
lubrication functions, an oil
must also effectively transfer
heat. Only about 60% of an
engines cooling is performed by
the engine coolant, and only on
the upper half of the engine.
The remaining 40% of an engines
cooling is performed mainly by
the engine oil.
Although a vehicle that is
recommended to use a 30 weight
oil can also use a 40 weight
oil, it is usually not needed.
You will gain absolutely no
benefit from using a thicker
viscosity oil if it is not
needed. The only time we
recommend a 40 weight oil, such
as AMSOIL's 10W-40, to a
customer in a passenger car or
light truck application is if
the vehicle's engine is
excessively worn and consumes
oil at a higher than normal rate
or if the vehicle is being used
for very severe duty, high load,
high temperature applications.
We hope this brief discussion
has answered your questions. If
we have not sufficiently
answered your questions or if
you would like an additional
explanation or recommendation
for your specific application
please email us using the link
at the bottom of this page.