AMSOIL PREMIUM PROTECTION 20W-50 100% SYNTHETIC MOTOR OIL

AMSOIL Premium Protection 20W-50 100% Synthetic Motor Oil delivers heavy-duty wear protection and thermal stability for engines that run hard, run hot, or rely on flat-tappet camshafts. It is built for the demands of classic muscle cars, air-cooled engines, high-mileage trucks, motorcycles with wet clutches, and diesel-powered equipment that needs a tough 20W-50.

Older engines and high-stress applications present a unique set of problems. Flat-tappet cams and high-tension valve springs generate extreme contact pressures that modern low-zinc oils simply are not designed to handle. Engines used for towing, hauling, or extended operation in hot climates face accelerated oxidation, viscosity breakdown, and deposit buildup that shorten component life. Conventional 20W-50 oils can lose viscosity under shear and cook off at high temperatures, leaving critical surfaces vulnerable.

HIGH-ZINC FORMULA FOR FLAT-TAPPET AND HIGH-PRESSURE COMPONENTS
Flat-tappet camshafts depend on a robust anti-wear chemistry that most current API SN and SP oils have deliberately reduced. Premium Protection 20W-50 is formulated with a heavy treatment of zinc dialkyldithiophosphate (ZDDP) and other anti-wear additives specifically to protect cam lobes, lifters, gears, bearings, and other high-pressure contact surfaces. This makes it a direct fit for pre-1980s V8 engines with flat-tappet cams, street rods, muscle cars like the Chevrolet Camaro Z/28, Ford Mustang Boss 302, Pontiac GTO, and Plymouth Road Runner, as well as older Harley-Davidson V-twins and other engines that were engineered around higher zinc levels.

RESISTS VISCOSITY LOSS UNDER SHEAR
A 20W-50 oil that shears down to a thinner grade under load defeats its own purpose. Premium Protection is engineered to resist viscosity loss due to mechanical shear, maintaining the thick protective film these engines were designed around. That film integrity matters in high-mileage engines with looser tolerances, air-cooled motorcycle and aircraft engines that see sustained elevated temperatures, and heavy equipment running long duty cycles.

CONTROLS OXIDATION AND HIGH-TEMPERATURE DEPOSITS
Synthetic base oils give Premium Protection a fundamental thermal advantage over conventional petroleum 20W-50 motor oils. Volatilization (burn-off), oxidation, and excessive deposit formation from high heat are greatly reduced. Viscosity thickening is controlled, which helps air-cooled and liquid-cooled engines run cleaner and cooler over time. For engines that consume more oil than normal on thinner viscosities, the heavier 20W-50 film can also help reduce oil consumption.

WET-CLUTCH COMPATIBLE FOR MOTORCYCLES AND POWERSPORTS
Premium Protection contains no friction modifiers, which makes it safe for motorcycles and other equipment with wet-clutch transmissions. It meets JASO MA requirements and is formulated to prevent clutch glazing and slippage. Riders running Harley-Davidson Sportsters, Honda CB series, Yamaha XS models, or any metric cruiser or touring bike calling for a 20W-50 can use this in both the engine and wet-clutch transmission without worry about clutch engagement issues.

DUAL-PURPOSE COVERAGE FOR GAS AND DIESEL ENGINES
One oil that covers both gasoline and diesel applications simplifies inventory for shops, farms, and mixed-fleet operators. Premium Protection meets API SL, SJ, SH, and SG for gasoline service, along with API CI-4+, CI-4, CH-4, CF, and CF-2 for diesel. It also carries approvals including Caterpillar ECF-1, Cummins 20071/20072/20076/20077, Mack EO-M+ and EO-M, MAN 271/3275, MTU Type 2, Volvo VDS-2 and VDS, Detroit Diesel 93K214, Mercedes-Benz 228.1/228.3/229.1, and ACEA A3/B3, E3, and E5. That breadth of coverage makes it a practical choice for older diesel pickup trucks, generators, stationary engines, and heavy equipment alongside its classic-car and motorcycle applications.

SPECIFICATIONS AND COMPATIBILITY
Premium Protection 20W-50 meets or exceeds the following specifications: API SL, SJ, SH, SG, CI-4+, CI-4, CH-4, CF, CF-2; ISO-L-EMA; JASO MA; ACEA A3/B3, E3, E5; Caterpillar ECF-1; Cummins 20071/20072/20076/20077; Mack EO-M+, EO-M; MAN 271/3275; MTU Type 2; Volvo VDS-2, VDS; Detroit Diesel 93K214; Mercedes-Benz 228.1, 228.3, 229.1. It is compatible with conventional and synthetic motor oils, though mixing will shorten oil life and reduce performance benefits. AMSOIL does not support extended drain intervals where oils have been mixed. Aftermarket oil additives are not recommended.

SERVICE LIFE
For diesel engine service, Premium Protection is recommended for up to 25,000 miles or one year in normal service and up to 15,000 miles or one year in severe service. For gasoline engine service, it is recommended for up to 15,000 miles or one year in both normal and severe service. Motorcycles, small engines, stationary engines, heavy equipment, and other applications should extend drain intervals based on oil analysis or follow the manufacturer-recommended interval. For best results, use AMSOIL Ea Full-Flow Oil Filters and replace at the time of oil change.