AMSOIL SIGNATURE SERIES 10W-30 100% SYNTHETIC MOTOR OIL

AMSOIL Signature Series 10W-30 100% Synthetic Motor Oil delivers the kind of protection that most 10W-30 oils simply cannot match, with 75% more wear protection than the industry standard demands and a guaranteed drain interval of up to 25,000 miles. Built for gasoline engines in cars, trucks, and SUVs that call for a 10W-30 viscosity, this is the oil professional engine builders reach for when durability and cleanliness are non-negotiable.

Modern gasoline engines run hotter and work harder than ever. Tighter tolerances, gasoline direct injection, and turbocharging all place enormous stress on motor oil. Stop-and-go driving, short trips, and extended intervals between oil changes compound the problem by accelerating sludge formation and deposit buildup. A conventional or even mid-tier synthetic 10W-30 can lose its protective edge well before the next scheduled change. The consequences show up as cam lobe wear, piston deposits, restricted oil passages, and reduced engine performance over time.

75% MORE PROTECTION AGAINST WEAR AND HORSEPOWER LOSS
In the Sequence IVA Engine Test (ASTM D6891), which simulates extended stop-and-go driving over 100 hours of idling and elevated-RPM cycles, AMSOIL Signature Series delivered an average cam wear measurement of just 20.28 micrometers, compared to the 90-micrometer industry-standard limit. That is 75% less wear than the test allows. AMSOIL used the lightest viscosity in the lineup, 0W-20, to further increase the severity of testing, and still dominated. The strong fluid film keeps metal surfaces separated under load, while robust anti-wear additives protect in metal-to-metal contact zones. For engines in Ford F-150s, Chevy Silverados, Toyota Tacomas, and other trucks and SUVs that commonly spec a 10W-30, this level of cam and piston protection translates directly to longer engine life and sustained horsepower output.

28% MORE ACID-NEUTRALIZING POWER THAN MOBIL 1
Signature Series carries a Total Base Number (TBN) of 12.5, measured by ASTM D2896. That heavy detergent loading gives it 28% more acid-neutralizing power than Mobil 1 Annual Protection Full Synthetic 5W-30, based on independent testing of both oils. Acid buildup is what degrades oil over time, leading to corrosion, deposits, and sludge. A higher TBN means the oil maintains its cleaning and protective capacity longer, which matters whether you are running this oil in a daily driver or pushing it toward its 25,000-mile drain interval. Signature Series also contains 50% more detergents than AMSOIL OE Motor Oil, helping keep oil passages clear and promoting consistent oil circulation throughout the engine.

90% BETTER SLUDGE PROTECTION
The Sequence VG Engine Test subjects a Ford 4.6L engine to 216 hours of sludge-inducing conditions. The industry standard allows up to 10% oil pick-up screen blockage before failure. Signature Series 5W-30 produced a screen virtually free of sludge, delivering 90% better protection against sludge than the standard requires (ASTM D6593). Engine failures caused by oil starvation from a plugged pick-up screen are preventable with the right oil. This formulation's detergent and dispersant system keeps contaminants suspended and moving to the filter rather than settling into critical oil passages.

TURBOCHARGER PROTECTION AGAINST COKING
Turbocharged engines in vehicles like the Ford F-150 3.5L EcoBoost, Chevy Equinox 1.5T, and Honda CR-V 1.5T generate extreme heat around the turbo bearing and shaft. When oil breaks down under that heat, it forms hard carbon deposits through a process called turbo coking, which restricts oil flow and eventually degrades turbo performance or causes outright failure. In the GM Turbo Coking Test, which consists of 2,000 extreme heat-soak cycles, Signature Series limited the temperature increase within the turbocharger to just 3.6%, compared to the 13% maximum allowed by the GM dexos1 Gen 2 specification. That is 72% better protection than the test requires. For anyone running a turbocharged GDI engine and searching for the best synthetic 10W-30 for turbo protection, this is a difficult result to beat.

100% LSPI PROTECTION
Low speed pre-ignition is a destructive phenomenon in modern GDI and turbocharged engines where the fuel-air mixture ignites before the spark plug fires. LSPI events can crack piston ring lands and cause catastrophic engine damage. AMSOIL Signature Series achieved zero LSPI events across five consecutive tests required by the GM dexos1 Gen 2 specification, delivering 100% protection against LSPI. The advanced detergent system is specifically formulated to minimize the deposit conditions that trigger LSPI in engines like the GM Ecotec, Ford EcoBoost, and other modern direct-injection powerplants.

OUTSTANDING VISCOSITY STABILITY UNDER EXTREME HEAT
In the Sequence IIIH Engine Test (ASTM D8111), conducted at oil temperatures of 304°F using a Chrysler 3.6L Pentastar engine, Signature Series showed only a 0.1% viscosity increase after the standard test length, compared to the 100% increase allowed by the industry standard. Even when the lab doubled the test to 180 hours using the same oil, viscosity increase reached just 49.6%, still well under the single-length threshold. The pistons were 40% cleaner than the standard required after the double-length run. This thermal durability means the oil resists breakdown and thickening even in high-heat operating conditions, maintaining consistent protection and flow throughout the drain interval.

SPECIFICATIONS AND COMPATIBILITY
AMSOIL Signature Series 10W-30 (ATM) meets or exceeds the following specifications: API SP (Resource Conserving), SN PLUS, SN; ILSAC GF-6A, GF-5, GF-4; ACEA A5/B5, A1/B1; Ford WSS-M2C205-A; Chrysler MS-6395; GM LL-A-025, 6094M, 4718M. It is compatible with other conventional and synthetic motor oils, though mixing will shorten the oil's life expectancy and reduce performance benefits. Aftermarket oil additives are not recommended.

SERVICE LIFE
Normal Service: Up to 25,000 miles, 700 hours of operation, or one year, whichever comes first, in personal vehicles not operating under severe service conditions.

Severe Service: Up to 15,000 miles, 700 hours of operation, or one year, whichever comes first. Severe service conditions include commercial or fleet vehicles, excessive idling, and frequent towing, hauling, plowing, or driving in dusty conditions. Modified engines (non-stock), racing vehicles, and vehicles using alternative fuels (E85, CNG, propane) are excluded from extended drain interval recommendations. Do not exceed 12,000 miles or one year with non-AMSOIL oil filters unless longer intervals are recommended by the vehicle manufacturer. Always change the filter when changing oil.