AMSOIL Preferred Customer Program

Synthetic Oil FAQs

Synthetic Oil FAQs

When oil filters were introduced in the early 1920s, many vehicle manufacturers began recommending changing the motor oil every 3,000 miles. Naturally, repair facilities and oil-change shops adhered to this recommendation for the customers they served. As engine and lubrication technology advanced through the later part of the century, vehicle manufacturers began recommending increasingly longer oil-change intervals. Quick lubes and other oil-change facilities, however, continued recommending 3,000-mile drain intervals, perpetuating what is now known as the "3,000-mile myth."

Most vehicle manufacturers today recommend much longer between oil changes, and many feature an on-board oil life monitor that uses driving habits to determine when the vehicle’s oil should be changed. Whether you follow the recommendation in your owner’s manual or choose an AMSOIL synthetic motor oil that lasts even longer, you’re sure to drive more than 3,000 miles between oil changes, and you’re sure to do so without damaging your vehicle’s engine.

AMSOIL Signature Series Synthetic Motor Oil is formulated using premium synthetic base oils, and the highest-quality additives, that provide extended-drain capabilities. Signature Series Synthetic Motor Oil achieves greater cleaning powers while providing better equipment protection over longer oil drain intervals. The unique synthetic formulation and robust TBN retention of AMSOIL Signature Series Synthetic Motor Oil work to resist oxidation and neutralize the acids that shorten the service lives of other oils. Its characteristic resistance to high-temperature volatility (burn-off) helps reduce oil consumption, while maintaining viscosity longer than other oils. Check the product data bulletin for specific recommendations.

Yes. Using AMSOIL synthetic motor oil has no affect on vehicle warranties. A federal law called the Magnuson-Moss Act (1975) prevents original equipment manufacturers from putting conditions on vehicle warranties attached to any product or service identified by brand, trade or corporate name, unless the manufacturer provides that product or service free of charge. This means consumers have the freedom to use aftermarket products of their choice without fear of losing the original limited or implied vehicle warranty. For additional information, visit, or contact the AMSOIL Technical Department at (715) 399-TECH (8324) or [email protected].

No. Extending oil change intervals will not void new vehicle warranties. To affect the vehicle warranty, it must be determined that the lubricant was directly responsible for the failure; if the oil didn’t cause the problem, the warranty cannot be voided, regardless of brand or length of time in use. For additional information, visit, or contact the AMSOIL Technical Department at (715) 399-TECH (8324) or [email protected].

First, AMSOIL INC. works closely with major additive companies to select the top-performing, and usually most expensive, passenger car and heavy-duty diesel motor oil additives. These additives have already passed all of the API licensing requirements in a petroleum- or synthetic-based formulation. Then, AMSOIL works with the additive company to maximize the amount of additive used and to boost the additive package in selected performance areas to achieve an optimum performing additive package for the intended application. This is unlike many other oil companies that, because additives are expensive, use the minimum amount of the least expensive additives required to meet the minimum API requirements.

AMSOIL then uses a combination of synthetic base stocks with known performance characteristics as replacements for the petroleum base stocks to optimize performance in areas of lubricity, volatility, viscosity index, oxidation and nitration resistance, pour point, flash point, deposit control, soot handling, emissions and many other areas as well. AMSOIL also uses a high-quality viscosity-index improver with outstanding viscosity and cleanliness properties. This replaces the inexpensive, low-quality viscosity-index improver used in standard API-licensed petroleum formulas. AMSOIL does laboratory bench tests and runs field tests to verify the superiority of the synthetic formula. AMSOIL continues to monitor the performance of the oil through close scrutiny of tens of thousands of oil analysis tests per year across a wide variety of vehicles all around North America and the world. AMSOIL INC. has been collecting used synthetic oil samples from passenger cars since 1982. No other oil company has such a vast database of the performance of synthetic lubricants over extended drain intervals. AMSOIL products and formulations outperform API-licensed oils because they are engineered for top performance from the very beginning.

Each vehicle manufacturer defines "normal" and "severe" driving conditions for its equipment; AMSOIL recommends owners check these definitions in their owner’s manual to determine the service condition in which they typically drive.

AMSOIL defines normal service as personal vehicles frequently traveling greater than 10 miles (16 km) at a time and not operating under severe service.

AMSOIL defines severe service for gasoline engines as turbo/supercharged engines, commercial or fleet vehicles, excessive idling, first-time use of AMSOIL synthetic motor oil in vehicles with over 100,000 miles without prior continuous use of AMSOIL synthetic motor oil, daily short-trip driving less than 10 miles (16 km), frequent towing, plowing, hauling or dusty-condition driving.

AMSOIL defines severe service for diesel engines as extensive engine idling, daily short-trip driving less than 10 miles (16km) or frequent dusty-condition driving.

See the AMSOIL Product Recommendation and Drain Interval Chart for additional information.

No. You can use whichever brand of filter you choose and AMSOIL synthetic motor oils will still be guaranteed to protect your vehicle for the advertised period. However, you will need to change your oil filter according to the filter manufacturer’s recommendations and top off the oil.

Yes. It is normal for vehicles to use some motor oil. AMSOIL recommends checking your oil level every time you fill your fuel tank.