Comparative Motor Oil Testing
API Motor Oil Testing:
AMSOIL Synthetic 10W-30 Motor Oil (ATM) and 10 competing conventional and synthetic 10W-30 motor oils were
subjected to a series of API motor oil tests. The competing oils included petroleum-based Castrol GTX Drive Hard,
Mobil Drive Clean, Pennzoil with Purebase, Quaker State Peak Performance and Valvoline, as well as synthetic-based
Valvoline Synpower, Quaker State, Castrol Syntec, Pennzoil and Mobil 1 SuperSyn Multi-Vehicle.
Seven API tests were run on the motor oils. The Thin-Film Oxygen
Uptake Test (TFOUT) measures the oxidation stability of engine oils. The High Temperature/High Shear Test (HTHS)
measures a lubricant’s viscosity under severe operating conditions. The NOACK Volatility Test measures the
evaporation loss of oils in high temperature service. Pour Point indicates the lowest temperature at which a fluid
will flow. Total Base Number (TBN) is the measurement of a lubricant’s reserve alkalinity for combating acids. The
Cold Cranking Simulator Test (CCS) measures a lubricant’s viscosity at low temperatures and high shear rates. The
Four-Ball Wear Test measures a lubricant’s wear protection properties. The impressive test results show AMSOIL
Synthetic 10W-30 Motor Oil outperformed the competitors in each test.
Thin-Film Oxygen Uptake (ASTM D-4742):
The Thin-Film Oxygen Uptake Test evaluates the oxidation stability of lubricating oils. A mixture of the test oil
and chemistries found in gasoline engine operation (oxidized/nitrated fuel, soluble metals and distilled water) are
placed in a test vessel, which is pressurized with oxygen and placed in a heated bath. Anti-oxidant breakdown is
evident when the oxygen pressure in the vessel rapidly decreases. At this point, the induction time (break point)
of the oil is recorded. As shown in the graph, AMSOIL Synthetic 10W-30 Motor Oil had the highest induction time of
all the tested oils. In fact, it didn’t reach its break point in over 500 minutes of testing.
The superior oxidation stability of AMSOIL Synthetic 10W-30 Motor Oil allows it to effectively resist the formation
of engine deposits and sludge, keeping engines running clean and efficient and extending oil life. It also resists
thickening, maintaining its superior wear protection and lubricating properties and maximizing fuel efficiency.
High Temperature/High Shear (ASTM
The High Temperature/High Shear Test measures a lubricant’s viscosity under severe high temperature and shear
conditions that resemble highly-loaded journal bearings in fired internal combustion engines. In order to prevent
bearing wear, it is important for a lubricant to maintain its protective viscosity under severe operating
conditions. The minimum High Temperature/High Shear viscosity for a 30 weight oil is 2.9 cP. As shown in the graph,
AMSOIL Synthetic 10W-30 Motor Oil surpasses this minimum standard and displayed the highest High Temperature/High
Shear viscosity in the group.
The superior viscosity retention of AMSOIL Synthetic 10W-30 Motor Oil in the face of severe temperature and shear
conditions allows it to provide continuous, unsurpassed protection for engine bearings, extending equipment life
and preventing wear.
NOACK Volatility (ASTM
The NOACK Volatility Test determines the evaporation loss of lubricants in high temperature service.The more motor
oils vaporize, the thicker and heavier they become, contributing to poor circulation, reduced fuel economy and
increased oil consumption, wear and emissions. A maximum of 15 percent evaporation loss is allowable to meet API SL
and ILSAC GF-3 specifications. As shown in the graph, AMSOIL Synthetic 10W-30 Motor Oil outperformed its nearest
competitor by over 30 percent.
The extremely low volatility of AMSOIL Synthetic 10W-30 Motor Oil allows it to maintain its superior protective and
performance qualities throughout extended drain intervals, even when faced with severe operating temperatures. In
addition, oil consumption and emissions are minimized and fuel efficiency is maximized.
Pour Point (ASTM D-97):
The Pour Point Test determines the lowest temperature at which a lubricant will flow when cooled under prescribed
conditions. The lower a lubricant’s pour point, the better protection it provides in low temperature service. As
shown in the graph, AMSOIL Synthetic 10W-30 Motor Oil has the lowest pour point of the tested oils.
The low pour point of AMSOIL Synthetic 10W-30 Motor Oil allows it to maintain its fluidity in extremely low
temperatures, reducing drag on moving vehicle parts, providing critical engine components with quick, essential
lubrication and easing startup in cold temperatures. Wear is greatly reduced and equipment life is extended.
Total Base Number (ASTM
Total Base Number (TBN) is the measurement of a lubricant’s reserve alkalinity, which aids in the control of acids
formed during the combustion process. The higher a motor oil’s TBN, the more effective it is in suspending
wear-causing contaminants and reducing the corrosive effects of acids over an extended period of time. As shown in
the graph, AMSOIL Synthetic 10W-30 Motor Oil has the highest TBN of the tested oils.
The high TBN of AMSOIL Synthetic 10W-30 Motor Oil allows it to effectively combat wear-causing contaminants and
acids, providing superior protection and performance over extended drain intervals.
Cold Crank Simulator (ASTM
The Cold Crank Simulator Test determines the apparent viscosity of lubricants at low temperatures and high shear
rates. Viscosity of lubricants under these conditions is directly related to engine cranking and startability. The
lower a lubricant’s cold crank viscosity, the easier an engine will turn over in cold temperatures. 10W motor oils
are tested at -25°C and must have a viscosity below 7000 cP to pass. As shown in the graph, AMSOIL Synthetic 10W-30
Motor Oil is well below the maximum requirement, while many of the competing oils barely pass.
The low cold crank viscosity of AMSOIL Synthetic 10W-30 Motor Oil reduces drag on moving engine parts and allows
engines to achieve critical cranking speed in extremely frigid temperatures. Engines turn over quickly and
dependably in the coldest winter temperatures.
Four Ball Wear (ASTM
The Four Ball Wear Test determines the wear protection properties of a lubricant. Three metal balls are clamped
together and covered with the test lubricant, while a rotating fourth ball is pressed against them in sliding
contact. This contact typically produces a wear scar, which is measured and recorded. The smaller the average wear
scar, the better the wear protection provided by the lubricant. As shown in the graph, AMSOIL Synthetic 10W-30
Motor Oil produced the smallest wear scar of the tested lubricants.
AMSOIL Synthetic 10W-30 Motor Oil provides unsurpassed protection against engine wear. Equipment life is extended,
and repairs, downtime and expenses are reduced.
AMSOIL INC. has been the leader in synthetic motor oil formulation since its
introduction of the world’s first API rated synthetic motor oil in 1972. By specializing exclusively in
synthetic lubricant technology, AMSOIL is able to optimize the most advanced chemistries available. The
“Genuine Synthetic PAO Formulated” designation displayed on AMSOIL packaging indicates that the oils are
formulated with Polyalphaolefin (PAO) synthetic base stocks. This chemistry is the industry’s premier base
stock technology. Unlike conventional mineral-based chemistries, AMSOIL PAO base stocks contain fully
saturated, hydrogenated molecules and are free of wax and other impurities. Combined with an exact balance of
premium additives, it delivers superior hot and cold temperature performance, resists oxidation and acid
formation and provides long-term wear protection. AMSOIL “Genuine Synthetic PAO Formulated” oils have
shattered the parameters of the most rigorous industry testing and set the standard for all other motor
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