Volatility and the NOACK Test
I have to keep adding oil to my engine?"
Volatization, the methods used
to test it and why AMSOIL decided customers would care.
When speaking about their
vehicles, motorists may comment that their auto "uses a little oil now
and then." Although many are positive that the vehicle is
"using" this oil, upon further questioning they often cannot
explain how or why or where exactly the oil disappeared. Is it leaking?
Certainly some vehicles leak an amount of oil out of seals, gaskets and
joints. But others that "use" oil have no leaks at all. So where
does this oil go? The oil goes through a process known as volatization, and
it can end up costing motorists more than just the price of a few quarts of
Why Oil Volatizes
After crude oil has been pumped from the ground, it is sent to a refinery
where it is distilled into its usable components. Distillation separates the
crude into fractions based on their individual boiling ranges. The crude is
Fractioning Tower separates the usable portions of
crude oil to obtain common end products.
each fraction boils off as a vapor, and then is condensed and subjected to
further processing. This boiling is essentially the same circumstance
occurring during volatization in an engine, with lighter molecules vaporizing
and heavier molecules remaining. In refining, this process can effectively
increase the amount of similar molecular structures in each fraction, and
therefore improve the stability and quality of each product refined. However,
even the final petroleum-based product still consists of a wide range of
hydrocarbon structures. These are sometimes referred to as a "chemical
This "chemical soup"
found in standard petroleum mineral oils contributes to many of their
shortcomings when compared with synthetic oils. Because these molecules
prevent uniformity, the oil has a tendency to deteriorate more rapidly. If
lighter fractions are present in the oil, they can boil off (or volatize)
which leads to oil consumption, oil thickening and a loss of performance.
Money to Burn?
Even though many motorists do not realize it, when they notice that their
vehicle is "using" oil they are often witnessing the effects of
simply buy extra oil to replace what they assume the motor has
"used" and check regularly to see if the level is low. But is
adding more mineral oil necessarily the best solution to the problem? What
they may in fact be doing by adding more petroleum-based mineral oil is
burning up their money.
For example, if an automobile
needs five quarts of mineral oil sold at $2 a quart to operate during a
3,000- mile drain interval, and the mineral oil used in the vehicle volatizes
and is replaced at a rate of one quart every 1,000 miles, the automobile
actually goes through 7 quarts of mineral oil during the drain interval and
the motorist spends an extra $4 per oil change interval on "topping
off" the levels. Considering that the average vehicle puts on 15,000
miles a year, $20 in extra oil is used to keep the oil levels sufficient.
But extra oil is not the only expense
motorists face when dealing with volatization. As motor oil goes through the
process of volatizing, the chemically lighter (or more volatile) portions are
always the first to "boil off" in the oil. This leaves the heavier,
less pumpable portions behind. This heavier oil cannot be relied upon to flow
easily and quickly to all of the engine components. The end result is
decreased fuel efficiency, premature component wear and deposit formation
within the engine. The expense to the motorist can be quite substantial.
The Synthetic Solution
Synthetic motor oils have a natural advantage over petroleum-based oils when
it comes to volatility. This is because synthetic oils are designed to have
uniform chemical structures. This eliminates the extra chemicals and
hydrocarbon structures (or "chemical soup") found in oils based
only in mineral stock. Because they contain less lighter chemical portions to
boil off, synthetic products lose less of their lubricating abilities to
AMSOIL Synthetic Motor Oils
maintain their viscosity and provide ongoing cold start protection, fuel
efficiency and reduced oil consumption.
An AMSOIL First
Surprisingly, volatility was not always considered when comparing motor oils.
Few oil companies published test results measuring an oil's volatility until
the 1980s, when AMSOIL became the first in the United States to publish NOACK Volatility
The NOACK Volatility test
apparatus. The grey box holds the oil
sample and heats it to 150ºC. Dry air is passed over the
sample to carry away the vapors which have boiled off.
In the NOACK Volatility Test the oil is heated to 150° C for a specified
period. Lighter oil fractions will "boil off," leading to oil
consumption, oil thickening and a loss of performance. The percentage lost,
by weight, due to this "boil-off" is reported.
The test has different passing
requirements depending on the weight of the oil being tested. For example,
10W-30 oil in the United States may lose up to 22 percent, by
weight, and still be "passable." However, with 20 percent gone, the
oil suffers significant performance deficits in characteristics such as
pumpability and lubricity.
a new specification, known as GF-3, allows a maximum of 15 percent loss.
European standards, which have been stricter for years, already limit high
quality oils to a maximum of 13 percent loss. AMSOIL 10W-30 loses only 6.76
percent to volatility.
AMSOIL reports these results
because they enable informed consumers to understand the value offered by
synthetic motor oils. Low oil volatility means reduced oil consumption rates,
maximum fuel efficiency and higher levels of performance for longer periods
I welcome the opportunity to work with you personally as your servicing
AMSOIL Dealer. Use the information on this website to contact me. You may also
check out the AMSOIL Corporate Website for product and
business opportunity information.