About the Subaru EJ25 Engine

This used Subaru EJ25 engine for sale suits Subaru enthusiasts and anyone looking to upgrade or install a new powerplant in their car. The boxer configuration has been synonymous with Subaru reliability and performance potential for decades, across many Subaru models. Additionally, due to its flat-four (horizontally opposed) configuration, the EJ25 lowers the vehicle's center of gravity, improving handling and stability.

The Subaru EJ25 engine for sale here has proven versatile across its 26-year production run , it powers everything from daily-driver Foresters and Outbacks (NA SOHC variants like the EJ251 and EJ253) up to high-performance WRX and STI applications (turbocharged DOHC variants like the EJ255 and EJ257). With a thriving aftermarket to back up owner choices for parts and upgrades, this boxer engine's distinct rumble and brawny construction have solidified its fame among Subaru fans worldwide.

Important Configuration Clarification

The live product page description states the EJ25 is an "inline 4-cylinder" , this is incorrect. The EJ25 is a flat-4 (horizontally opposed) boxer engine, NOT an inline-4. The cylinders are arranged horizontally in two banks of two, with each bank facing outward to opposite sides of the vehicle. This is Subaru's signature engine configuration and produces the characteristic "Subaru rumble" sound.

Subaru EJ25 Engine Family: What You Need to Know

The Subaru EJ25 is the 2.5 liter member of Subaru's broader EJ-series flat-4 boxer engine family. The EJ25 was produced in multiple variants across a 26-year production run (1995-2021), with both naturally aspirated and turbocharged configurations.

EJ25 Variant Breakdown

NA SOHC Variants (Standard Subaru Applications)

EJ251 (1999-2004)

• HP: 165 HP at 5,600 RPM
• Torque: 166 lb-ft at 4,000 RPM
• Valvetrain: SOHC per bank, 16 valves
• Compression: 10.0:1
• Common Applications: Impreza (1999-2004), Forester (1999-2003), Outback (1999-2004), Legacy (1999-2004)
• GSC: "ej251 hp" #1 RANKING, "ej251 for sale" pos 19.0

EJ252 (1995-1999, less common)

Earlier 2.5L SOHC variant

HP: 165 HP

EJ253 (2005-2013)

• HP: 173 HP at 6,000 RPM
• Torque: 166-170 lb-ft at 4,000 RPM
• Valvetrain: SOHC per bank, 16 valves with AVLS (Active Valve Lift System) on some variants
• Common Applications: Impreza (2005-2011), Forester (2006-2010), Outback (2005-2009), Legacy (2005-2009), Baja (2006)

Updated EJ251 with refined combustion and emissions

NA DOHC Variants (Limited)

EJ254 (1997-2003)

• DOHC NA variant
• Used in some Outback / Legacy GT applications
• Less common

Turbocharged DOHC Variants (Performance Subaru Applications)

EJ255 (2002-2014)

• HP: 227-255 HP (varies by year and application)
• Torque: 217-244 lb-ft
• Valvetrain: DOHC per bank, 16 valves with AVCS variable valve timing
• Turbocharger: IHI VF series with intercooler
• Common Applications: WRX (2002-2014), Forester XT (2004-2013), Legacy GT (2005-2009)

EJ257 (2004-2021)

• HP: 300-305 HP at 6,000-6,400 RPM , the WRX STI engine
• Torque: 290 lb-ft at 4,000 RPM
• Valvetrain: DOHC per bank, 16 valves with AVCS
• Turbocharger: Larger IHI VF series or aftermarket
• Common Applications: WRX STI (2004-2021)
• GSC: "cosworth ej257" pos 2.3, "ej257 for sale" pos 19.7, "ej257 crate engine" pos 17.8

Cosworth EJ257

• Special performance variant produced through Subaru / Cosworth partnership
• Forged internals (crankshaft, connecting rods, pistons)
• Closed-deck block (vs open-deck stock) for higher boost capability
• Power potential: 400-500+ HP with proper supporting modifications
• Highly desired for serious performance builds
• Strong GSC presence: "cosworth ej257" pos 2.3

EJ25 Variants Summary Chart

Key Engineering Features

• Flat-4 (Horizontally Opposed) Boxer Configuration: Lower center of gravity, smoother than inline-4
• Open-Deck Aluminum Block: Lighter weight, but contributing factor in head gasket issues on NA variants
• Aluminum Cylinder Heads: All variants
• SOHC or DOHC Per Bank: Variant-dependent
• AVCS Variable Valve Timing: Standard on later DOHC variants (EJ255 / EJ257 from various years)
• Sequential Multi-Port Fuel Injection: All variants (some late applications direct injection)
• Longitudinal Mount: Engine mounted lengthwise, paired with Subaru's symmetrical AWD

Honest Disclosure: Head Gasket Service Items (NA EJ25 Variants)

• This is the most important thing to know about NA EJ25 engines: head gasket failures are essentially a guaranteed service item on high-mileage SOHC EJ25 engines (EJ251 / EJ253):
• The issue: Open-deck block design combined with the head gasket material used results in eventual external coolant leaks or oil-coolant cross-contamination
• Service interval: Typically occurs at 100,000-150,000 miles
• Symptoms: External coolant weeping (smell of coolant, slow loss), or in worse cases coolant in oil (milky oil)
• Cost: $1,500-3,000 for proper head gasket service including replacement head gaskets, machined head surfaces, and updated fasteners
• Critical: When buying a used NA EJ25 engine, head gasket service history is essential information

This is widely documented as a known Subaru service item, NOT a defect. Subaru even acknowledged the issue with extended warranties on some affected models. Properly serviced (with updated multi-layer steel head gaskets), the EJ25 NA can run reliably for another 100,000+ miles.

• Turbo Variants (EJ255 / EJ257) generally have fewer head gasket issues due to the higher-quality components used in performance applications, but face other concerns:
• Ringland failures: Particularly at high boost on stock internals (most common reason for EJ257 rebuilds)
• Rod bearing wear: At high RPM and high boost
• Carbon buildup on valves: From direct injection variants

Why Choose a Used Subaru EJ25 Engine?

• Cost savings vs reman (variant-dependent, $4,500 used vs $4,500-7,500 reman plus core for turbo variants)
• Variant matching , we identify EJ251 vs EJ253 vs EJ255 vs EJ257 vs Cosworth EJ257
• Direct OEM fit for Impreza, Forester, Outback, Legacy, WRX, WRX STI, Baja
• Strong aftermarket , the EJ family has one of the largest aftermarkets of any Japanese engine
• Performance potential , especially EJ257 / Cosworth EJ257 for serious builds
• Symmetrical AWD compatibility , direct mate for Subaru transmissions

Here at Vaz Auto Solutions, you'll find this Subaru EJ25 engine for sale at the most reasonable price possible, with variant identification, donor vehicle confirmation, head gasket condition assessment (critical EJ25 service area), turbocharger inspection (turbo variants), and complete testing.

Vehicle Compatibility

Direct Fit (NA EJ251 / EJ253 Variants):

Direct Fit (Turbo EJ255 / EJ257 Variants):

Condition and Inspection

• Variant verified (EJ251 / EJ253 NA SOHC, EJ255 turbo, EJ257 STI, or Cosworth EJ257)
• Donor vehicle confirmed (Impreza, Forester, Outback, Legacy, WRX, WRX STI, Forester XT, Legacy GT, Baja)
• All 4 cylinders compression tested
• Oil pressure verified at idle and operating speed
• Head gasket condition assessed (critical EJ25 service item especially NA SOHC variants)
• External coolant leak inspection (NA EJ25 typical failure mode)
• Cylinder head condition assessed (aluminum heads, warping check)
• Turbocharger condition verified (EJ255 / EJ257 variants, including shaft play, oil seals)
• Wastegate operation verified (turbo variants)
• AVCS variable valve timing function tested (later DOHC variants)
• Open-deck aluminum block inspection
• Ringland condition assessment where observable (EJ257 known service item)
• Spark plug condition documented (4 plugs)
• Coil-on-plug function verified
• Coolant system function verified
• Miles from donor vehicle documented where available
• Variant correctly identified (EJ251 / EJ253 / EJ255 / EJ257 / Cosworth EJ257)
• All 4 cylinders compression tested
• Head gasket condition assessed , critical EJ25 service area especially NA variants
• Turbocharger condition verified on EJ255 / EJ257 turbo variants
• Open-deck block inspection
• AVCS variable valve timing tested
• Donor vehicle and mileage documented
• Cross-reference assistance across Subaru EJ25 family applications
• WRX / STI performance build consultation
• Free freight pallet delivery to all 50 states
• 15 day replacement warranty on internal defects
• Subaru EJ25 family specialist support team