Subaru Forester Quiz
Starting and operating

Fuel octane rating

In this manual: Starting and operating
Foreword — 1Warranties — 5How to use this Owner’s Manual — 5Vehicle symbols — 1Safety precautions when driving — 14General information — 1Illustrated index — 7Function settings — 1Seat, seatbelt and SRS airbags — 77Keys and doors — 169Climate control — 54Audio — 189Interior equipment — 38Starting and operating — 85Driving tips — 49In case of emergency — 21Appearance care — 17Maintenance and service — 103Specifications — 21Consumer information and Reporting safety defects — 31
~1min read

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).

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.

Test yourself

A quick Subaru Forester quiz: every answer comes with an explanation and a link to the manual page.