Amsoil Authorized Dealers John & Zenaida Cardell

20W-50 (ARO)

Amsoil Premium Protection 20W-50 Synthetic Motor Oil (ARO)

Product Highlights

For use in both gasoline and diesel engines. Offers multi-functionality and wear protection. Ideal for applications where the extra protection of a higher-viscosity oil is desired. Excellent for motor homes and older vehicles, as well as many types of modern equipment and compatible with some motorcycles.

AMSOIL Amsoil 20W-50 Premium Protection Synthetic Motor Oil is formulated to provide superior protection and performance in a wide variety of demanding applications. Its unique combination of synthetic base oils and a superior additive package results in a formulation that exceeds the requirements of most gasoline or diesel applications that call for 20W-50 or 20W-50 motor oil. Amsoil 20W-50 Premium Protection Synthetic Motor Oil is ideal for high-mileage vehicles and high-stress vehicles subject to hot temperatures, heavy hauling, trailer pulling or off-road use. It provides the extra anti-wear protection required by engines with flat-tappet cams and high-tension valve springs. AMSOIL Amsoil 20W-50 Premium Protection Synthetic Motor Oil offers flexibility and performance beyond conventional oils.

Package Sizes (ASM)

AROQT (AROQT-CA)QuartCase of 12
ARO1G (ARO1G-EA)GallonEach
ARO1G (ARO1G-CA)GallonCase of 4
AROTP (AROTP-EA)2.5-GallonEach
AROTP (AROTP-CA)2.5-GallonCase of 2
ARO30 (ARO30-EA)30-Gallon DrumEach
ARO55 (ARO55-EA)55-Gallon DrumEach

AMSOIL, the leader in automotive synthetic lubrication, produced the world’s first API qualified synthetic motor oil in 1972. Trust the extensive experience of AMSOIL The First in Synthetics® to do the best job protecting your engine.

  • High-zinc formula guards against wear
  • Ideal for flat-tappet cams
  • Resists deposits to help keep engines clean
  • Convenience of use for gas and diesel engines

Superior Wear Protection

Amsoil 20W-50 Premium Protection Synthetic Motor Oil is high-viscosity oil engineered to protect against metal-to-metal contact. It resists viscosity loss due to shear and is formulated with a heavy treatment of zinc and other anti-wear additives for excellent protection of gears, bearings, cam lobes and other high-pressure components in engines and transmissions. Amsoil 20W-50 Premium Protection Synthetic Motor Oil helps extend equipment life.

Wet-Clutch Compatible

Amsoil 20W-50 Premium Protection Synthetic Motor Oil contains no friction modifiers, making it ideal for motorcycles, maintenance equipment and other wet-clutch transmission applications. Formulated to prevent clutch glazing and slippage, it helps ensure smooth clutch engagement and long-term, dependable transmission operation. Amsoil 20W-50 Premium Protection Synthetic Motor Oil reduces clutch wear for extended transmission life.

Resists Oxidation and High-Temperature Breakdown

Amsoil 20W-50 Premium Protection Synthetic Motor Oil is formulated to overcome the thermal deficiencies common to conventional petroleum oils. Volatilization (burn-off), oxidation and excessive deposit formation from high heat are greatly reduced. Viscosity thickening is controlled and engines run cleaner, promoting cooler operation and long engine life in air- or liquid-cooled engines. In addition, the higher viscosity of AMSOIL 20W-50 Synthetic Motor Oil may help reduce motor oil consumption in equipment that experiences higher-than-normal usage rates when lower-viscosity lubricants are installed.

Extends Drain Intervals in Gasoline and Diesel Engines

Superior synthetic base oil and additive technology exceeds the requirements of both gasoline and diesel engines. Premium Protection Motor Oil is designed to neutralize acids, disperse soot and last longer in service than conventional oils.


AMSOIL Amsoil 20W-50 Premium Protection Synthetic Motor Oil is recommended for air- and liquid-cooled, large or small gasoline and diesel engines, transmissions and chaincase applications where 20W-50 oils are required with any of the following specifications:

  • API SL, SJ, SH, SG
  • API CI-4+, CI-4, CH-4, CF, CF-2
  • Caterpillar* ECF-1
  • JASO MA (Motorcycle)
  • MAN* 271/3275
  • MTU Type 2
  • Cummins* 20071/20072/20076/20077
  • Volvo*, VDS-2, VDS
  • Mack* EO-M+, EO-M
  • ACEA A3/B3, E3, E5
  • MB 228.1, 228.3, 229.1
  • Detroit Diesel* 93K214


AMSOIL Synthetic 20W-50 Premium Protection Motor Oil is compatible with conventional and synthetic motor oils. Mixing AMSOIL motor oils with other oils, however, will shorten the oil life expectancy and reduce the performance benefits. AMSOIL does not support extended drain intervals where oils have been mixed. Aftermarket oil additives are not recommended for use with AMSOIL Synthetic Oils.

Amsoil Premium Protection Synthetic Oil
Kinematic Viscosity @ 100°C, cSt (ASTM D445)14.6
Kinematic Viscosity @ 40°C, cSt (ASTM D445)95.9
Viscosity Index (ASTM D2270)158
NOACK Volatility, % weight loss (g/100g) (ASTM D5800)6.5
Flash Point, °C (°F) (ASTM D92)226 (439)
Fire Point, °C (°F) (ASTM D92)240 (264)
Pour Point, °C (°F) (ASTM D97)-42 (-44)
Four-Ball Wear Test, Scar, mm (ASTM D4172)0.48
High-Temperature/High-Shear Viscosity, cP (ASTM D5481)4.3
TBN (Total Base Number)12.1

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