Subaru 2.5L FB25 BOXER: years, specs & known problems

By CarWhere Research · Updated

The FB25 is Subaru's 2,498 cc, DOHC 2.5-liter BOXER four, introduced in the 2011 Forester. It replaced the older EJ25 and powers the Forester, Outback, Legacy, Crosstrek and Impreza. Ratings rose from 170 hp to 182 hp with direct injection in 2019; Subaru rates 2025-on versions at 180 hp and 178 lb-ft.

Subaru introduced the engine in the 2011 Forester with a new bore and stroke, double overhead cams instead of single, chain-driven camshafts instead of belts, and dual AVCS variable valve timing. It reached the Legacy and Outback for 2013, when Subaru called it the FB series and rated it 173 hp and 174 lb-ft. A 2015 update brought 175 hp. The 2019 Forester version added direct injection, higher compression and Auto Stop/Start, with Subaru saying nearly 90 percent of its parts were new; Subaru Corporation lists it as the FB25, 2,498 cc with a 94 × 90 mm bore and stroke, 182 hp and 176 lb-ft.

Since the 2025 Forester and 2026 Outback, Subaru rates the 2.5L at 180 hp and 178 lb-ft. The engine in the Forester Hybrid and Crosstrek Hybrid is a newly developed 2.5L Atkinson/Miller-cycle BOXER, and Subaru's US releases don't give it an engine code. The smaller FB20 2.0L sibling (148–152 hp) powered the Impreza from 2012 and the Crosstrek from 2013. The early FB oil-consumption class settlement and the 2019 PCV-valve recall are the main official records for this engine.

2.5L FB25 BOXER at a glance

Subaru FB25 2,498 cc horizontally opposed four-cylinder, DOHC, US 2011–present: model years, fuel and peak Subaru-published output by version
EngineModel yearsFuelPeak hpPeak torque (lb-ft)Documented problemsRecalls
Port-injected FB25 (2011–2018)2011–2018Gasoline17517410
Direct-injection FB25 (2019–present)2019–presentGasoline18217801

CarWhere lists 1 documented problem and 1 NHTSA recall for the 2.5L FB25 BOXER, each with a source. Part of the Subaru BOXER engines (EJ25, FB25, FA20, FA24) family.

Port-injected FB25 (2011–2018)

The first FB25: 170 hp in the Forester, 173 hp in the 2013 Legacy and Outback, and 175 hp after the 2015 update.

Port-injected FB25 (2011–2018) specifications

Port-injected FB25 (2011–2018): design facts (2011–2018)
SpecificationValue
Displacement2,498 cc (152 cu in)[1]
ValvetrainDOHC, chain-driven camshafts, dual AVCS variable valve timing[1]
Change from EJ25New bore and stroke; DOHC instead of SOHC; chain instead of belt[1]
Series nameFB series (Subaru, 2013 Outback)[6]
Engine codeFB25 (2015 Legacy/Outback, per Subaru Corporation)[7]
LayoutHorizontally opposed: pistons face each other side to side, cancelling inertia forces[8]
FB20 sibling2.0L FB engine; 148 hp in the 2012 Impreza, 152 hp with direct injection from 2017[9]

Port-injected FB25 (2011–2018) horsepower and torque by year

Port-injected FB25 (2011–2018): Subaru-published horsepower (hp) and torque (lb-ft) by model year and application
Model yearsApplicationHorsepower (hp)Torque (lb-ft)Source
2011Forester 2.5X170 hp at 5,800 rpm; 174 lb-ft at 4,100 rpm170174[1]
2013Legacy and Outback 2.5i173174[2]
2014Forester 2.5i170 hp at 5,800 rpm170174[3]
2015Outback 2.5iTorque spread over a broader rpm range175174[4]
2015Legacy 2.5i175174[5]

"—" means we could not confirm the figure from a primary source.

Which vehicles have the Port-injected FB25 (2011–2018)?

Models and model years offered with the Port-injected FB25 (2011–2018)
ModelModel yearsNotes
Forester2011–20182.5X / 2.5i
Legacy2013–20192.5i
Outback2013–20192.5i
XV Crosstrek / Impreza2012–2016Used the FB20 2.0L, not the FB25

Port-injected FB25 (2011–2018) problems and what to check

Excess oil consumption in early FB engines (class settlement) (2011–2015)

Moderate

A federal court approved a class settlement in 2016 over excess oil consumption in early FB-series engines. FB25 vehicles covered include 2011–2014 automatic and 2011–2015 manual Forester 2.5L, the 2013 Legacy and Outback 2.5L and 2013–2014 manual Legacy and Outback 2.5L, up to specified VINs. The court opinion records Subaru's position that elevated claims involved fewer than 1% of vehicles and that design countermeasures brought rates down to a normal background level by 2014. Subaru denied the claims.[10]

Symptoms

  • Oil level low between changes
  • Low-oil warning light

Check before buying

  • Ask a Subaru retailer whether oil-consumption bulletin repairs (including any short block replacement) were done on the VIN
  • Check the oil level at the inspection and ask for oil-change records

Program: Yaeger v. Subaru of America (D.N.J.), final approval Aug. 31, 2016: oil-consumption repairs covered for 8 years or 100,000 miles, whichever comes first; free oil-consumption test, failed above one-third of a quart in 1,200 miles

Direct-injection FB25 (2019–present)

Revised for the 2019 Forester with direct injection, higher compression and Auto Stop/Start. Rated 182 hp and 176 lb-ft at launch, and 180 hp and 178 lb-ft since the 2025 Forester.

Direct-injection FB25 (2019–present) specifications

Direct-injection FB25 (2019–present): design facts (2019–present)
SpecificationValue
Engine codeFB25[18]
2020 Outback listingFB25 2,498 cc, 94 × 90 mm, DOHC direct injection[19]
Hybrid engine (not coded)Newly developed 2.5L Atkinson/Miller-cycle BOXER in the 2025 Forester Hybrid[20]
Hybrid system output194 hp combined (2026 Crosstrek Hybrid)[21]
Hybrid engine, Japan-spec rating118 kW (160 PS) at 5,600 rpm, 209 N·m (Japan-model Crosstrek, Subaru in-house figures)[22]
Displacement2,498 cc[18]
Bore × stroke94 × 90 mm[18]
ValvetrainDOHC, 16 valves, AVCS[18]
Fuel injectionDirect injection[11]
New partsNearly 90 percent new versus the previous 2.5L[12]
Fuel87 AKI regular[18]
EPA listing, 2019 Forester2.5 L four only, CVT (AV-S7)[23]
Crosstrek 20262.5L standard on every Crosstrek[24]
Impreza 20272.5L, 180 hp, standard across the lineup[17]

Direct-injection FB25 (2019–present) horsepower and torque by year

Direct-injection FB25 (2019–present): Subaru-published horsepower (hp) and torque (lb-ft) by model year and application
Model yearsApplicationHorsepower (hp)Torque (lb-ft)Source
2019Forester182176[11]
2020Outback and Legacy182 hp at 5,800 rpm; 176 lb-ft at 4,400 rpm182176[12]
2021Crosstrek Sport and Limited182176[13]
2024Impreza RS182178[14]
2025Forester180178[15]
2026Outback180178[16]
2027ImprezaSubaru quotes horsepower only180—[17]

"—" means we could not confirm the figure from a primary source.

Which vehicles have the Direct-injection FB25 (2019–present)?

Models and model years offered with the Direct-injection FB25 (2019–present)
ModelModel yearsNotes
Forester2019–present
Outback2020–present
Legacy2020–2025
Crosstrek2021–presentSport and Limited from 2021; standard on every trim from 2026
Impreza2024–presentRS from 2024; standard for 2027

Direct-injection FB25 (2019–present) recalls

NHTSA safety recalls related to the Direct-injection FB25 (2019–present) (campaign numbers link to NHTSA)
NHTSA campaignReportedVehiclesSummary
19V8562019-12-022019 Crosstrek, Forester and Ascent51,613 vehiclesThe aluminum PCV valve can separate and its pieces can enter the engine, causing a loss of power. Dealers replace the valve, and replace the short block if the pieces cannot be found, free of charge.

2.5L FB25 BOXER issues by model

The same engine shows up on these known-issues pages, with model-specific details.

Related Subaru research

Confirm a car really has the 2.5L FB25 BOXER.

The engine a Subaru left the factory with is part of its build record. The CarWhere Subaru build sheet reconstructs factory colors, options and packages from licensed VIN-level build data — availability is checked free, and it is $9.99 only when detailed build data is found for that VIN.

Subaru build sheet by VIN

Frequently asked questions

What is the difference between the Subaru FB25 and EJ25?

The FB25 replaced the EJ25 starting with the 2011 Forester. Subaru says it uses a different bore and stroke, double overhead cams instead of single, and chain-driven camshafts instead of belts, which Subaru says lowers servicing costs.

Does the FB25 burn oil?

Early FB engines were the subject of a class settlement approved in 2016. It covered certain 2011–2015 Foresters and 2013–2014 Legacys and Outbacks with oil-consumption repairs for 8 years or 100,000 miles. The court opinion records Subaru's position that design countermeasures had brought rates to normal levels by 2014.

How much horsepower does the Subaru 2.5 make?

Subaru rated the FB25 at 170 hp in the 2011 Forester, 173–175 hp in the 2013–2019 Legacy and Outback, and 182 hp after the 2019 direct-injection update. Since the 2025 Forester and 2026 Outback it is rated 180 hp and 178 lb-ft.

Is the FB25 used in the Subaru hybrids?

Subaru describes the 2025 Forester Hybrid and 2026 Crosstrek Hybrid engine as a newly developed 2.5-liter Atkinson/Miller-cycle BOXER, with 194 hp total system output. Its US releases don't give it an engine code.

What is the FB20?

The FB20 is the 2.0-liter FB-series sibling. It debuted at 148 hp in the 2012 Impreza, gained direct injection and 152 hp for 2017, and powered base Crosstreks. FB20 Imprezas and XV Crosstreks were also part of recalls 18V772 (valve springs) and 19V744 (PCV valve).

Sources

Ratings are Subaru-published figures as cited; descriptions are CarWhere’s own summaries of the sources below. Repair costs appear only where a source states them and vary by shop and region.

  1. Subaru Forester Gains New Infotainment Refinements for 2012 — Subaru of America, Inc. (media.subaru.com)
  2. 2013 Subaru Legacy Debuts New Powertrain, EyeSight and Revised Styling (Aug. 2012) — Subaru of America, Inc. (media.subaru.com)
  3. Subaru Reveals All-New 2014 Forester Crossover SUV (Oct. 30, 2012) — Subaru of America, Inc. (media.subaru.com)
  4. Subaru Introduces All-New 2015 Outback at New York International Auto Show (Apr. 16, 2014) — Subaru of America, Inc. (media.subaru.com)
  5. Subaru Introduces All-New 2015 Legacy Sedan (Feb. 5, 2014) — Subaru of America, Inc. (media.subaru.com)
  6. 2013 Subaru Outback Debuts New Powertrain, EyeSight and Revised Styling (Aug. 2012) — Subaru of America, Inc. (media.subaru.com)
  7. Subaru Reaches 15 Million Production of Horizontally-Opposed "Boxer" Engines (Feb. 17, 2015) — Subaru Corporation (subaru.co.jp)
  8. 50th Anniversary of Subaru Horizontally-Opposed "Boxer" Engine (May 10, 2016) — Subaru Corporation (subaru.co.jp)
  9. Subaru Introduces All-New, U.S.-Built 2017 Impreza (2016) — Subaru of America, Inc. (media.subaru.com)
  10. Yaeger v. Subaru of America, No. 1:14-cv-04490 (D.N.J.), opinion granting final approval of oil-consumption settlement (Aug. 31, 2016) — U.S. District Court for the District of New Jersey (govinfo.gov)
  11. All-New 2019 Subaru Forester Debuts at New York International Auto Show (Mar. 28, 2018) — Subaru of America, Inc. (media.subaru.com)
  12. Subaru Debuts All-New Sixth-Generation 2020 Outback (Apr. 17, 2019) — Subaru of America, Inc. (media.subaru.com)
  13. 2021 Subaru Crosstrek Debuts with Refreshed Design, Suspension and an Available 2.5 Liter Engine (July 9, 2020) — Subaru of America, Inc. (media.subaru.com)
  14. Subaru Debuts the All-New 2024 Impreza Compact Car (Nov. 17, 2022) — Subaru of America, Inc. (media.subaru.com)
  15. Subaru Debuts All-New 2025 Forester SUV (Nov. 16, 2023) — Subaru of America, Inc. (media.subaru.com)
  16. Subaru Debuts All-New 2026 Outback with Bold New Styling, Upgraded Technology (Apr. 16, 2025) — Subaru of America, Inc. (media.subaru.com)
  17. Subaru Announces Pricing on 2027 Subaru Impreza — Subaru of America, Inc. (media.subaru.com)
  18. World Premiere of All-New 2019 Forester (US-spec specifications, Mar. 29, 2018) — Subaru Corporation (subaru.co.jp)
  19. World Premiere of All-New 2020 Subaru Outback (US-spec specifications, Apr. 18, 2019) — Subaru Corporation (subaru.co.jp)
  20. Subaru Introduces All-New 2025 Forester Hybrid with Next-Generation Hybrid Powertrain (Feb. 6, 2025) — Subaru of America, Inc. (media.subaru.com)
  21. Subaru Announces New 2026 Crosstrek Hybrid with Next-Generation Hybrid Powertrain (Jan. 16, 2025) — Subaru of America, Inc. (media.subaru.com)
  22. Subaru Debuts Next-Generation Hybrid System (Oct. 17, 2024) — Subaru Corporation (subaru.co.jp)
  23. EPA engine listings: 2019 Subaru Forester AWD — U.S. EPA / DOE (fueleconomy.gov)
  24. Subaru Announces Pricing on 2026 Crosstrek Including New 2026 Crosstrek Hybrid (July 16, 2025) — Subaru of America, Inc. (media.subaru.com)

More Subaru tools

Independent reference compiled by CarWhere — not affiliated with or endorsed by Subaru of America, Inc. or Subaru Corporation. Subaru and the model names are trademarks of their owners.