AMSOIL 100% Synthetic Motor Oil

The Complete Guide to AMSOIL Synthetic Motor Oil

AMSOIL invented the modern synthetic motor oil category in 1972 when founder Albert J. Amatuzio formulated the world's first API-qualified synthetic motor oil. Five decades later, AMSOIL still sets the benchmark for synthetic lubrication — the Signature Series remains the only major-brand synthetic motor oil that publishes its full third-party ASTM test data publicly, and it consistently outperforms Mobil 1 Annual Protection, Pennzoil Platinum, Royal Purple High Performance, Castrol Edge Extended Performance, and Valvoline Restore & Protect in head-to-head wear, oxidation, deposit, and cold-flow testing.

Signature Series — 25,000-Mile Drain Intervals, 75% More Protection

Signature Series (product codes ASL for 5W-30, ASM for 0W-20, ATM for 10W-30, AZO for 0W-30, ALM for 5W-20, AZF for 0W-40, AMR for 5W-50, and the new 0W-16) is AMSOIL's flagship motor oil. It provides 75% more engine protection against horsepower loss and wear than required by the GM dexos1 Gen 3 standard — the toughest gasoline-engine specification in the industry. With 25,000-mile or 1-year drain intervals (15,000 in severe service), Signature Series saves time, money, and reduces environmental waste from used motor oil. Pair it with an AMSOIL Ea oil filter rated for the same interval.

XL Extended-Life — 12,000-Mile Drains on a Budget

XL Synthetic Motor Oil (product codes XLF for 5W-30, XLM for 5W-20, XLZ for 0W-20, XLT for 10W-30, XLO for 10W-40) delivers 12,000-mile / 1-year drain intervals with outstanding protection. Boosted detergents keep engines cleaner longer. The right pick for budget-conscious drivers who want significantly longer drain intervals than conventional or OE-spec oils without the flagship Signature Series price.

OE Synthetic — The Easiest Upgrade From Conventional

OE Synthetic Motor Oil (product codes OEF for 5W-30, OEM for 5W-20, OEX for 0W-20, OEZ for 0W-16, OET for 10W-30, plus 0W-40) is formulated for OEM-recommended drain intervals. It's an easy, affordable upgrade from conventional or synthetic-blend oil to true 100% synthetic protection — covering nearly every late-model Ford, GM, Stellantis, Toyota, Honda, Hyundai/Kia, and European application.

100% Synthetic Hybrid Motor Oil — Engineered for HEV and PHEV Engines

Hybrid engines operate differently than conventional gas-powered cars. Frequent stop/start cycles, lower operating temperatures, and longer idle periods cause fuel dilution, water condensation, and accelerated oil contamination. AMSOIL 100% Synthetic Hybrid Motor Oil (product codes HE008 for 0W-8, HE016 for 0W-16, HE020 for 0W-20) is specifically engineered to combat these unique challenges. It delivers powerful protection against sludge, deposits, and wear in Toyota Prius, RAV4 Hybrid, Camry Hybrid, Honda CR-V Hybrid, Accord Hybrid, Ford Maverick Hybrid, F-150 PowerBoost, Hyundai/Kia hybrid models, and all other HEV and PHEV applications.

Z-ROD — High-Zinc Protection for Classic Cars and Hot Rods

Modern motor oils have reduced zinc/phosphorus (ZDDP) levels to protect catalytic converters in late-model vehicles. But classic cars, muscle cars, and hot rods with flat-tappet camshafts need that ZDDP for proper cam and lifter wear protection. AMSOIL Z-ROD (product codes ZRT for 10W-30, ZRF for 10W-40, ZRR for 20W-50) is formulated with high zinc/phosphorus content specifically for these vintage engines, plus rust and corrosion inhibitors that protect collector vehicles during long-term storage between shows and drives.

Premium Protection — Heavy-Duty High-Zinc Synthetic

Premium Protection (product codes AMO for 10W-40, ARO for 20W-50) is a heavy-viscosity, high-zinc synthetic motor oil engineered for high-performance, modified, flat-tappet, and high-mileage engines that demand a thicker oil film. Ideal for muscle cars, sports cars, towing applications, and engines operating under heavy loads or sustained high temperatures. The high-zinc formula provides exceptional anti-wear protection where it's needed most.

100% Synthetic High-Mileage — For Engines Over 75,000 Miles

Vehicles past 75,000 miles face unique challenges: dried or shrunken seals, increased oil consumption, and accumulated deposits. AMSOIL High-Mileage Synthetic Motor Oil (product codes HMF for 5W-30, HMM for 5W-20, HMZ for 0W-20, HMT for 10W-30) contains seal conditioners that help rejuvenate aging seals — reducing leaks and oil consumption — while extra detergents clean up existing deposits.

DOMINATOR® Synthetic Racing Oil — For Competition Engines

DOMINATOR (product codes RD20 for 5W-20, RD30 for 10W-30, RD40 for 10W-40, RD50 for 15W-50, RD60 for SAE 60) is purpose-built for high-performance and racing engines. Engineered to withstand elevated RPM, extreme temperatures, and shock-loading common to circle track, drag racing, sprint cars, road racing, and endurance applications. The high-zinc/phosphorus (ZDDP) formula delivers maximum wear protection while a proprietary friction modifier maximizes horsepower and torque.

How AMSOIL Compares to Mobil 1, Pennzoil, Royal Purple, and Castrol

In head-to-head independent testing using industry-standard ASTM methods, AMSOIL Signature Series consistently outperforms Mobil 1 Annual Protection, Royal Purple High Performance, Pennzoil Platinum, Castrol Edge Extended Performance, and Valvoline Restore & Protect in Sequence IVB wear protection, Sequence IIIH oxidation resistance, cold-pour point, deposit control, and TBN retention. AMSOIL is the only major synthetic brand that publishes its full third-party test data publicly at amsoil.com — every other brand limits comparisons to internal data.

Buying AMSOIL Synthetic Motor Oil in Florida and Across the U.S.

As an Independent AMSOIL Dealer based in Dade City, Florida, 1stsynthetic.com ships the full AMSOIL synthetic motor oil lineup factory-direct anywhere in the United States. Tampa Bay daily drivers running Signature Series ASL on their turbocharged GDI engines, Lakeland and Wesley Chapel hybrid owners using HE020 in their Toyota and Honda hybrids, Polk County classic-car owners protecting flat-tappet engines with Z-ROD ZRT, and racers across the U.S. running DOMINATOR RD30 — all order through 1stsynthetic.com to support an Independent Dealer while getting factory-direct AMSOIL pricing. Become a Preferred Customer to save 25% off retail on every motor oil order.