How Long Does Synthetic Motor Oil Last?

Longer Lasting AMSOIL Signature Series SAE 5W-30 Synthetic Motor Oil

Generally speaking, synthetic motor oil will nearly always last longer than conventional oil, saving you time and money. But your specific synthetic oil change interval will depend on several factors, including operating conditions, motor oil quality and personal preference.

Why Does Oil Lose its Effectiveness?
Extreme heat hastens chemical breakdown (oxidation), altering the oil’s chemistry and preventing it from lubricating, cooling and protecting as designed. Sludge can form, which clogs narrow oil passages and prevents oil from reaching vital components, causing wear. Oxidation can also lead to increased oil viscosity, which negatively affects energy efficiency. Ultimately, the oil loses its effectiveness and must be changed.
Contaminant build-up also affects oil life. Motor oil is formulated with detergent and dispersant additives responsible for holding dirt, soot (in diesel engines) and other contaminants in suspension and preventing them from depositing on engine surfaces or forming sludge. These additives are sacrificial in nature, meaning once they’re depleted, the oil’s effectiveness suffers and it must be changed.

Better Raw Materials Equal Better Oil
Like any other product, quality plays a big role, and in the case of motor oil helps determine service life and effectiveness. Synthetic motor oil is formulated using higher-quality raw materials than conventional oil, allowing it to perform better and last longer.

AMSOIL Signature Series Synthetic Motor Oil, for example, is guaranteed for 25,000 miles/700 hours of operation/one year, whichever comes first, in normal service (15,000 miles in severe service). Its synthetic base oils don’t contain the impurities inherent to conventional oils, allowing it to more effectively resist chemical breakdown and extreme heat. Signature Series is also formulated with high-quality additives that effectively neutralize contaminants for long service life.

By lasting longer than other oils, Signature Series offers the benefits of changing oil less often, saving you time and money.

Refine your search

Filter by

Look Up Guide
Get the Latest News
Connect with AMSOIL
Connect with AMSOIL
Connect with AMSOIL
Two Ways To Save