AMSOIL 10W-30 100% Synthetic High-Mileage Motor Oil

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AMSOIL 10W-30 100% Synthetic High-Mileage Motor Oil

AMSOIL 10W-30 100% Synthetic High-Mileage Motor Oil is a purpose-built SAE 10W-30 formulation for gasoline engines that have crossed 75,000 miles and need a more robust maintenance program than a standard motor oil. The formulation pairs boosted detergency with seal conditioners and a thermally stable synthetic base oil so older engines stay clean, hold compression, and resist the leaks and consumption that creep in as miles accumulate.

Built for engines past 75,000 miles

Drivers are keeping vehicles on the road longer as new-vehicle pricing and repair costs climb. Engines that have logged tens of thousands of miles run with worn seals, settled deposits, and looser tolerances that conventional additive packages were never tuned for. The 10W-30 grade targets that life stage with an additive shift toward cleanup, sealing, and viscosity stability rather than the lighter chemistry built for showroom-fresh tolerances.

Engine cleanliness verified by independent testing

Deposits and sludge reduce engine performance and efficiency over time. Independent testing of AMSOIL 0W-20 100% Synthetic High-Mileage Motor Oil in the modified Sequence VH Test (ASTM D8256) measured a 67 percent reduction in sludge after the switch. In the TEOST 33C Test (ASTM D6335) required by the ILSAC GF-6 specification, the same formulation delivered up to 62 percent better deposit prevention than Valvoline Full Synthetic High-Mileage with MaxLife Technology 0W-20 and Mobil 1 High-Mileage 0W-20 Full Synthetic Motor Oil. The 10W-30 grade carries the same chemistry into a heavier viscosity for engines designed around an SAE 10W-30 service fill.

Durable viscosity for engines that have lost compression

As cylinders and piston rings wear, engines lose the ability to seal the combustion chamber, and the loss shows up as reduced horsepower, blow-by, and oil thinning. The 10W-30 grade maintains a consistent fluid film at high operating temperatures, with a Kinematic Viscosity at 100 degrees Celsius of 11.3 cSt and a Viscosity Index of 148 per ASTM D445 and ASTM D2270, helping an aging engine seal combustion pressure and protect bearings under load.

Oil-consumption control and low volatility

Oil consumption is one of the most common complaints in older engines, and a volatile base oil accelerates the loss. The 10W-30 grade posts a NOACK Volatility of 4.5 percent weight loss in the ASTM D5800 test, well below the 15 percent maximum allowed by ILSAC GF-7A and GF-6A. Lower NOACK means fewer top-offs between drain intervals and less in-grade viscosity drift at the end of the change cycle, with a Flash Point of 230 degrees Celsius (ASTM D92) reinforcing thermal stability under hard use.

Seal conditioning and leak protection

Aging seals shrink and harden, which lets oil weep past valve covers, oil-pan gaskets, and front-and-rear main seals. The 10W-30 grade carries a boosted dose of seal conditioners that swell and re-elasticize the elastomer compounds inside the engine, helping stop existing weeps and slowing the development of new ones. Elevated detergency works alongside the conditioners to break down sludge masking worn seals, so the conditioning effect reaches the elastomer surfaces.

OEM and industry specifications

The 10W-30 grade is API licensed and meets API SQ, API SP, and API SN Plus with backward coverage to earlier API categories. ILSAC coverage includes GF-7A, GF-6A, and GF-5. The formulation also meets GM 4718M and 6094M, Chrysler MS-6395, and Ford WSS-M2C205-A, covering most domestic and import gasoline cars, light trucks, and SUVs that originally called for an SAE 10W-30.

Recommended applications and service intervals

Use AMSOIL 10W-30 100% Synthetic High-Mileage Motor Oil in any gasoline engine whose owner manual specifies an SAE 10W-30 meeting one or more of the API, ILSAC, or OEM specifications listed above. The grade is ideal for higher-mileage cars, light trucks, SUVs, and vans that have crossed the 75,000-mile threshold and benefit from the heavier in-grade viscosity, seal conditioners, and boosted detergency the High-Mileage chemistry provides.

• Normal service: up to 12,000 miles or one year, whichever comes first, in personal vehicles not operating under severe service.
• Severe service: follow the severe-service drain interval prescribed by the vehicle manufacturer in the owner manual.
• Not recommended for engines that call for a different SAE viscosity grade or for racing, modified, or alternative-fuel applications outside the published specifications. Confirm the right grade with the AMSOIL Vehicle Lookup Guide.
• Outside the United States and Canada, follow the OEM service interval published for the local market.

The formulation is compatible with other conventional and synthetic motor oils and can be topped off in an emergency. Mixing oils shortens the oil life expectancy and reduces the synthetic performance benefits, and extended drain intervals are not supported on a mixed sump. Aftermarket oil additives are not recommended with AMSOIL synthetic motor oils. Pair the oil with an AMSOIL Oil Filter sized for the chosen drain interval.

Typical technical properties

Order AMSOIL 10W-30 High-Mileage Motor Oil

AMSOIL 10W-30 100% Synthetic High-Mileage Motor Oil ships in a quart bottle (HM1030QT-EA), a case of 12 quarts (HM1030QT-CA), and a gallon jug (HM10301G-EA). Using AMSOIL synthetic lubricants does not void a new vehicle or equipment manufacturer warranty, and all AMSOIL lubricants and filters are covered by the AMSOIL Limited Warranty. Match the right grade for an aging Honda, Toyota, Ford, Chevy, GMC, Dodge, Jeep, Subaru, Nissan, or Hyundai with the AMSOIL Vehicle Lookup Guide, compare the broader lineup in the Car Oil Guide, then order AMSOIL 10W-30 100% Synthetic High-Mileage Motor Oil.

Frequently asked questions