What The Last Subaru Flat-Six Engine Model Costs Today

The flat-six engine has been around for generations, though its unique shape and construction mean it has limited-use cases in today’s cars. That didn’t stop Porsche from perfecting the flat-six engine over generation after generation of their 911, while Subaru offered flat-six power to shoppers for years, too.

Subaru’s prowess with flat or ‘boxer’ engines is well known. They don’t build any other type of engine, and nobody sells more flat-configuration engines than Subaru does. Today, Subaru’s flat-six engine has come and gone, and they only make four-cylinder gas engines. Below, we’ll look back at the flat six and pinpoint the location, time, and cause of its death– as well as the engine that came along to replace it.

The Life and Times Of The Subaru Flat Six

Let’s start with some context for those unfamiliar. A flat-six engine has two rows of three cylinders with staggered spacing that fire towards each other, since they’re arranged at a 180-degree angle. If you can imagine a V6 engine that’s been squashed flat, you’re in the right ballpark. This style of engine is the stuff of just two automakers: Porsche and Subaru. In recent years, Porsche only built flat-four engines (all turbocharged) for its 714 models, and flat-six engines mainly for the 911. In this type of engine, the pistons fire at the tires, sparring back and forth like the gloves of battling boxers. That’s why flat four or flat six engines are sometimes called Boxer engines, though this convention is mostly a Subaru thing. When you’re talking about Subarus, you can use ‘flat’ or ‘boxer’ interchangeably when referring to the engine, which doesn’t mind being called either.

Though most Subarus in modern history had a flat-four engine under the hood, Subaru used to have a flat-six engine as an up-level option for select models that let shoppers choose a signature powerplant that flexed some engineering muscle. In the decades prior to the flat-six engine’s demise, you’d find it under the hood of Subaru models, including the XVR, before it became further popularized in the Tribeca (which is a used SUV steal in 2025) and then took center stage as a well-known premium engine for the Legacy and Outback siblings that would eventually carry the 3.6-liter flat-six to its grave.

After years of service and dedication helped build a loyal following of Subaru flat-six enthusiasts, market forces eventually spelled the demise of the so-called 3.6R, which officially died at the end of the 2019 model year as both the Legacy and Outback were in line to receive a fresh new boxer engine. Though the Legacy and Outback would both call 2019 their last model year with a flat-six power available under their hood, Subaru announced the change to the Legacy first, and the Outback about two months later. This means that the 2019 Subaru Outback was very likely the last Subaru to ever have the 3.6-liter flat-six bolted up, may it rest in peace.

Related

Subaru Shares Something In Common With Porsche, And It’s Not The Boxer Engine

These brands are making the worst part of car ownership a little easier to live with.

Cause Of Death

In 2019, engineers had been busily preparing a new engine to replace the so-called ‘EZ’ flat six, which was losing relevance and getting old. Partly, that’s because Subaru just launched this engine and let it be. The EZ flat-six was initially a 3-liter unit that debuted in the 2001 Subaru Outback H6. By 2010, that 3-liter unit was replaced by an updated 3.6-liter unit in all applications.

And then, nothing happened.

No updates, no major revisions, no tweaks for some more power or a few more MPGs. The 256-horsepower engine went on unchanged for the next decade until its eventual departure for the afterlife. As automakers were pushing further and further into the limits of gas engine fuel efficiency, the EZ flat six continued from the sidelines, untouched by the considerable engineering resources Subaru was putting into its four-cylinder boxer engines and safety technologies during the same era. Many Subaru press releases came and went, highlighting the improvements made to the 2.5-liter boxer four-cylinder, and if the flat-six was mentioned at all, it was simply to confirm that it remained on the options list in case anyone wanted it. While it’s unclear when Subaru decided that there wouldn’t be a next-generation flat six, this EZ engine had become severely outgunned by next-generation competitor engines that were rapidly coming to market using less gas to make more power.

One of these was the EZ’s replacement, a 2.4-liter engine from the FA family. For 2019, the EZ flat-six engine remained on sale until the end of the year, though its replacement was hitting showrooms as the all-new 2019 Subaru Ascent rolled out. This was Subaru’s largest SUV ever, and the first model to debut the latest four-cylinder boxer engine with the latest tech, right in the heart of the SUV scene where shoppers would take notice. The new engine used direct fuel injection and a high compression ratio alongside a twin-scroll turbo and active valve timing to help deliver peak torque from just 2,000 RPM. Now in line with its modern competition, the latest FA turbo four was more eager across more of its rev range, and retained the family boxer growl at full throttle where most drivers will find its power delivery to be more than plenty.

Given the competition and market forces at the time, the EZ’s replacement had to offer shoppers a win-win situation when compared. Mission accomplished: the new flat-four turbo had 16% more torque than the outgoing EZ, made that torque at much lower revs, and used 12% fewer gas dollars to do it.

Related

Subaru Ascent Generations: Everything You Need To Know In One Place

See all generations of the Subaru Ascent: discover information about every model year and check out what was changed

What You’ll Pay Today and Some Advice Before You Do

According to data from AutoTempest.com, setting a budget for the low to mid-twenties will see you into a relatively low-mileage copy of the last Subaru powered by a six-cylinder boxer engine, the 2019 Outback 3.6R. Selection seems relatively plentiful at this price point, with many units counting 40,000 to 60,000 miles on their odometers. Very low-mileage units with less than 25,000 miles of use will push closer to the $30,000 mark. Though this isn’t the most powerful or fuel-efficient engine you’ll find in a used crossover for the money, it is a pleasing and proven performer that shouldn’t give you any headaches if you care for it properly, which it isn’t too difficult to do.

Related

Subaru Caves Under Tariff Pressure, Jacks Up Prices

Subaru is raising prices, citing market conditions. A clear code for “tariff-related.”

Between 40,000 and 60,000 miles, your Outback may need some maintenance inspections and care for its air filter, transmission fluid, and brake fluid. The service schedule in the Outback’s warranty and maintenance guide has the full scoop. Proper maintenance and care will help keep your flat-six ticking reliably for years to come.

Sources: Autotempest, Subaru, J.D. Power