Subaru Crosstrek Owners Manual: Fuel octane rating

Using a gasoline with a lower octane rating can cause persistent and heavy knocking, which can damage the engine.

Do not be concerned if your vehicle sometimes knocks lightly when you drive up a hill or when you accelerate. Contact your SUBARU dealer if you use a fuel with the specified octane rating and your vehicle knocks heavily or persistently.

RON

This octane rating is the Research Octane Number.

AKI

This octane rating is the average of the Research Octane and Motor Octane numbers and is commonly referred to as the Anti Knock Index (AKI).

Unleaded gasoline

The neck of the fuel filler pipe is designed to accept only an unleaded gasoline filler nozzle. Under no circumstances should leaded gasoline be used because it will damage the emission control system and may impair driveability and fuel economy.