In the current lineup, the Subaru Outback uses four-cylinder engines only.
This article explains the engine options today, notes there is no contemporary six-cylinder option, and looks back at when a flat-six was available in earlier generations.
Current engine options
Here are the two four-cylinder engines you might encounter under the Outback's hood, depending on trim and model year.
- 2.5-liter horizontally opposed four-cylinder (boxer) producing about 182 horsepower and 178 lb-ft of torque; standard with Subaru's CVT and all-wheel drive.
- 2.4-liter turbocharged boxer-four producing around 260 horsepower and 277 lb-ft of torque; available in the higher-end Outback XT trims and typically requiring premium gasoline; paired with an automatic transmission and standard all-wheel drive.
For most buyers, the 2.5L engine provides adequate daily performance and best fuel economy, while the turbo 2.4L offers stronger acceleration at the cost of higher fuel use and fuel requirements.
A look back at the six-cylinder era
Subaru did offer a six-cylinder option in some Outbacks in earlier generations. The 3.6-liter horizontally opposed six (commonly referred to as the 3.6R) appeared in late-2000s to early-2010s models, delivering more power but lower fuel efficiency than the four-cylinder options. That six-cylinder option was eventually discontinued as Subaru focused on more efficient four-cylinder engines for the Outback.
The 3.6-liter flat-six option
The 3.6-liter H6 offered in certain Outbacks provided a smoother, stronger power delivery, but it came with higher fuel consumption and added vehicle weight. It is now rare and largely limited to older model years in the used market.
Why the shift to four cylinders?
Subaru cites efficiency, emissions, weight, and durability as reasons for emphasizing four-cylinder engines across its lineup. The modern 2.5L and 2.4L turbo boxer-four engines deliver competitive performance with better real-world fuel economy while preserving standard all-wheel drive and rugged practicality.
Practical considerations for buyers
The choice between engine options often comes down to how you plan to use the vehicle—daily commuting vs. highway cruising, towing needs, and willingness to pay for higher-octane fuel. The turbo 2.4L can noticeably improve acceleration, especially in highway merge scenarios, but it will typically cost more at the pump and in initial purchase price.
- Pros of 4-cylinder options: better fuel economy, lower ownership costs, and a strong reliability track record.
- Cons of the historical six-cylinder option: higher fuel consumption and fewer used-model options today.
In short, if you want an Outback today, expect a four-cylinder engine, with the turbocharged variant available for those seeking extra performance.
Summary
The Subaru Outback is powered by four-cylinder engines in its current generation, with two engine options. A six-cylinder option existed in past generations but has since been discontinued in favor of the more efficient four-cylinder lineup. This aligns with Subaru’s broader shift toward improved fuel economy while preserving standard all-wheel drive and the model’s rugged practicality.