AMSOIL 5W-20 100% Synthetic High-Mileage Motor Oil
Preventive maintenance that includes high-quality lubricants is key for keeping vehicles safe and dependable for the long haul. AMSOIL 100% Synthetic High-Mileage Motor Oil is designed specifically for the unique demands of high-mileage engines, helping extend the life of your vehicle. It delivers purpose-built protection at a time in your vehicle's life where it could benefit from more-robust maintenance. It cleans and protects engines with boosted detergency and an additive package that fights oil breakdown and oil leaks.
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Product data sheets
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AMSOIL 5W-20 100% Synthetic High-Mileage Motor Oil
AMSOIL 5W-20 100% Synthetic High-Mileage Motor Oil is a fully synthetic gasoline engine oil engineered for vehicles with more than 75,000 miles on the odometer. The 5W-20 grade pairs a boosted detergent and dispersant package with enhanced anti-wear additives and a concentrated dose of seal conditioners that targets the wear, deposit, and oil-loss issues that develop as engines age. The formulation is API licensed and protects normal-service drivers for up to 12,000 miles or one year between changes.
Engineered for high-mileage gasoline engines
Aging engines develop their own service profile: ring and bore wear let combustion gases blow past pistons, deposits collect on rings and in the valvetrain, oil consumption climbs, and elastomer seals harden until they begin to weep oil. AMSOIL 5W-20 100% Synthetic High-Mileage Motor Oil is purpose-built for that stage of service rather than diluted from a standard passenger-car formula. More cleaning power and seal-conditioning action are concentrated into a 100 percent synthetic base oil, so engines past the 75,000-mile mark keep running cleaner and tighter.
Sludge cleanup in the modified Sequence VH test
Sludge begins as oxidized oil and combustion residue and ends as a varnish layer that smothers oil-control rings, restricts feed passages, and accelerates wear. In the modified Sequence VH engine test (ASTM D8256), AMSOIL 100% Synthetic High-Mileage Motor Oil reduced sludge by 67 percent, based on independent testing of the AMSOIL 0W-20 viscosity. Total engine sludge climbed from 0 to 3.12 over 178 hours on the prior fill, then dropped to 1.0 by 272 hours after the changeover, evidence that the formulation actively cleans existing deposits rather than only slowing new ones.
Up to 62 percent better deposit prevention
Deposit control inside the piston ring belt and on hot upper-engine surfaces is the single best predictor of long-term oil consumption and compression. In the industry-standard TEOST 33C test (ASTM D6335) required by the ILSAC GF-6 specification, AMSOIL 100% Synthetic High-Mileage Motor Oil produced 15.4 mg of total deposits, compared with 39.3 mg for Valvoline Full Synthetic High-Mileage with MaxLife Technology 0W-20 and 40.5 mg for Mobil 1 High-Mileage 0W-20 Full Synthetic Motor Oil, for up to 62 percent better deposit prevention than the competitive products tested. Results are based on independent testing of the AMSOIL 0W-20 viscosity against the Valvoline (batch J2622C5) and Mobil 1 (batch 11022L21A 6606) products purchased in December 2022.
Durable viscosity, oil-consumption control, and leak prevention
AMSOIL 5W-20 100% Synthetic High-Mileage Motor Oil maintains proper film thickness in extreme operation, holding shear stability so the oil keeps sealing combustion chambers as cylinders and rings wear. The synthetic base stocks are thermally stable across a wide temperature range and resist volatility, with NOACK volatility of 7.7 percent weight loss in ASTM D5800. Lower volatility means less oil boils off the hot upper engine and ends up in the intake tract or catalyst, which directly slows consumption between changes. A boosted dose of seal conditioners restores aging elastomer seals and helps stop the slow leaks that often appear at the front and rear main, valve covers, and oil pan with age.
API licensed for current passenger-car service
The 5W-20 grade carries API SQ, SP, and SN Plus service categories, ILSAC GF-7A, GF-6A, and GF-5 ratings, GM dexos1 Gen 3 (which supersedes dexos1 Gen 2 and 6094M), Chrysler MS-6395, and Ford WSS-M2C930-A, WSS-M2C945-A, WSS-M2C945-B1, WSS-M2C960-A1, and WSS-M2C970-A1. The American Petroleum Institute license confirms that the formulation meets and exceeds the requirements commonly found in current passenger-car owner manuals.
Recommended applications and service intervals
AMSOIL 5W-20 100% Synthetic High-Mileage Motor Oil is intended for naturally aspirated and turbocharged gasoline passenger cars and light trucks that specify an SAE 5W-20 grade and call for any of the API, ILSAC, GM, Chrysler, or Ford specifications listed above. It is the right choice for vehicles past 75,000 miles where oil consumption, minor leaks, or accumulated deposits have begun to show up between services.
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 listed in the vehicle owner manual. Severe conditions typically include heavy towing or hauling, frequent short trips, dusty environments, plowing, and commercial or fleet duty.
Modified engines, racing vehicles, and engines running alternative fuels such as E85, CNG, or propane fall outside the high-mileage service profile and should follow the engine builder or vehicle manufacturer interval.
Outside the United States and Canada, follow the vehicle manufacturer recommended drain interval.
AMSOIL 5W-20 100% Synthetic High-Mileage Motor Oil is compatible with conventional and other synthetic motor oils, but mixing shortens oil life and reduces performance benefits. Aftermarket oil additives are not recommended for use with AMSOIL synthetic motor oils. Pair each oil change with a fresh AMSOIL Oil Filter or an OEM-quality filter, and check oil level regularly between services.
Typical technical properties
Property
Value
Kinematic Viscosity at 100 C, cSt (ASTM D445)
8.8
Kinematic Viscosity at 40 C, cSt (ASTM D445)
49.4
Viscosity Index (ASTM D2270)
158
CCS Viscosity, cP at -30 C (ASTM D5293)
5191
Flash Point, C (ASTM D92)
228
Fire Point, C (ASTM D92)
242
Pour Point, C (ASTM D97)
-42
NOACK Volatility, percent weight loss (ASTM D5800)
7.7
Total Base Number (ASTM D2896)
10.0
High-Temperature High-Shear Viscosity at 150 C, cP (ASTM D5481)
2.8
Order AMSOIL 5W-20 High-Mileage Motor Oil
AMSOIL 5W-20 100% Synthetic High-Mileage Motor Oil is available in a quart bottle (HM520QT-EA), a case of 12 quarts (HM520QT-CA), a gallon jug (HM5201G-EA), and a 55 gallon drum (HM52055-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. Confirm application match for the year, make, model, and engine with the AMSOIL Vehicle Lookup Guide, compare options across the gasoline car oil lineup in the AMSOIL Car Oil Guide, then order AMSOIL 5W-20 100% Synthetic High-Mileage Motor Oil.
I purchased my AMSOIL products by word of mouth testimonial from someone who I trust concerning topics such as automotive care, and they were right! My 2006 Nissan Frontier 4.0L is experiencing a rebirth in fuel economy! It's always been a great little truck, but since changing over to your product I believe that my engine is not working as hard as it was, and it has 207,000+ miles on it! Thanks Amsoil, I'm telling family and friends about it!
By Leroy from Kingman, AZ on July 17, 2026.
Would recommend this to a friend.
Great company
Very happy with Amsoil products.
By Thomas from California on July 17, 2026.
Would recommend this to a friend.
Great product
Switched to Amsoil for the price and reviews, change oil at 7k and still looks clean
High-mileage motor oil is a passenger-car engine oil formulated for vehicles with more than 75,000 miles on the odometer. The differences from a standard motor oil are practical: more detergent and dispersant chemistry to clean accumulated sludge and varnish, additional seal-conditioning agents to soften and reswell aged elastomer seals, and an additive system tuned for the lower compression and higher oil consumption that come with engine wear.
When should the switch be made to a high-mileage oil?
The 75,000-mile point is the design target for AMSOIL 5W-20 100% Synthetic High-Mileage Motor Oil and is also the practical inflection point where small leaks, faint exhaust smoke at startup, or topping off a quart between oil changes begin to appear. Drivers can switch sooner if those symptoms show up earlier, particularly on engines with a long history of severe service or extended short-trip operation.
Will AMSOIL 5W-20 High-Mileage stop existing oil leaks?
The boosted dose of seal conditioners restores aging seals and helps prevent leaks. Hard, shrunken elastomer seals can re-swell and reseat over a few thousand miles of service, which slows or stops weeping at common points like the valve covers, oil pan, and front and rear main seals. The formulation does not repair physically damaged seals, blown gaskets, or split lines, which still require mechanical repair.
How long can AMSOIL 5W-20 High-Mileage stay in service?
Normal service is up to 12,000 miles or one year, whichever comes first, in personal vehicles inside the United States and Canada that are not operating under severe service. For severe-service profiles, including heavy towing, frequent short trips, plowing, dusty operation, and commercial or fleet duty, follow the severe-service drain interval prescribed in the vehicle owner manual.
Which specifications does AMSOIL 5W-20 High-Mileage meet?
The 5W-20 grade is API licensed and meets API SQ, SP, and SN Plus, ILSAC GF-7A, GF-6A, and GF-5, GM dexos1 Gen 3 (supersedes dexos1 Gen 2 and 6094M), Chrysler MS-6395, and Ford WSS-M2C930-A, WSS-M2C945-A, WSS-M2C945-B1, WSS-M2C960-A1, and WSS-M2C970-A1. Confirm the recommended grade and specification with the AMSOIL Vehicle Lookup Guide before ordering.
Does using AMSOIL motor oil void a new-vehicle warranty?
No. Using AMSOIL synthetic lubricants or practicing extended drain intervals does not void a new vehicle or equipment manufacturer warranty, and all AMSOIL lubricants and filters are covered by the AMSOIL Limited Warranty.
