2008 Subaru Outback Owner's Manual - Page 443

& Fuel: GAS STATION REFERENCE & Fuel octane rating 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). Refer to "Fuel" section in this manual. ! 2.5-liter non-turbo models Use only unleaded gasoline with an octane rating of 87 AKI or higher. ! 2.5-liter turbo models Use premium unleaded gasoline with an octane rating of 91 AKI or higher. For temporary purposes if premium unleaded gasoline is not available, you may use regular unleaded gasoline with an octane rating of 87 AKI or higher. For optimum engine performance and driveability, it is required that you use premium grade unleaded gasoline. ! 3.0-liter models Use unleaded gasoline with an octane rating of 91 AKI or higher. Regular unleaded gasoline with an octane rating of 87 AKI or higher may be used. However for optimum engine performance and driveability, it is recommended that you use 91 AKI or higher grade unleaded gasoline. You may experience reduced output, poor accelerator response, and reduced fuel economy when using gasoline with an octane rating lower than 91 AKI, depending on your driving habits and conditions. If you experience any of these conditions while using a lower octane rated fuel, you may want to return to using 91 AKI octane rated fuel as soon as possible. Additionally, if your vehicle knocks heavily or persistently, or if you are driving with heavy loads such as when towing a trailer, the use of 91 AKI or higher grade unleaded gasoline is required. & Fuel capacity: 16.9 US gal (64 liters, 14.1 Imp gal) & Engine oil: Use only API classification SM with the words "ENERGY CONSERVING" or ILSAC GF-4, which can be identified with the ILSAC certification mark (Starburst mark). & Engine oil capacity: 2.5-liter models: 4.2 US qt (4.0 liters, 3.5 Imp qt) 3.0-liter models: 5.8 US qt (5.5 liters, 4.8 Imp qt)