Motor Oil and Filtration Guide

Motor Oil & Filtration Guide

Applications require specific lubricant properties to deliver maximum performance and protection. AMSOIL carefully tailors its synthetic lubricants under the strictest quality control standards to provide the required properties for the intended application. Mixing  AMSOIL synthetic lubricants is not only unnecessary, it may lead to reduced performance and even equipment failure.


Automatic transmission fluids offer a perfect example. Some transmissions require lubricants that contain specific frictional characteristics to reduce, or eliminate, clutch slippage, while other transmissions may require different frictional requirements. Mixing fluids recommended for different performance specifications may lead to a host of problems, including erratic shifting and transmission failure.


In some applications, mixing lubricants may not lead to equipment failure, but it will reduce performance. For example, if AMSOIL Signature Series 5W-30 Synthetic Motor Oil is installed in a vehicle, and its owner adds AMSOIL OE Synthetic 5W-30 Motor Oil to top off the engine if Signature Series isn’t available, the vehicle will continue to operate perfectly; Signature Series and OE Synthetic Motor Oil share a similar chemistry, and formulations of the same viscosity can be safely mixed. However, mixing lubricants will shorten Signature Series' life expectancy and reduce its performance benefits. AMSOIL does not support extended drain intervals where oils have been mixed.


To minimize the risk of performance- and warranty-related issues due to improper mixing, AMSOIL does not recommend mixing AMSOIL synthetic lubricants.



See why car enthusiasts, engine builders and racers also depend on AMSOIL lubricants to provide world-class wear protection for their vehicles.

AMSOIL Devoted to Protection™: Sequence IIIG Test

The American Petroleum Institute sets the minimum standards oil must pass to ensure it will provide adequate protection. One of these standards, the Sequence IIIG Test, subjects oil to 100 hours of use at 302°F- 100° higher than normal operating temperatures- and measures its ability to prevent wear, deposits and more. Find out how our Signature Series 5W-30 Synthetic Motor Oil performed. To learn more, visit