The SUBARU EJ253 is a 2,457 cc, flat-four petrol engine produced between 2004 and 2019. It features DOHC, 16-valve configuration with multi-port fuel injection and naturally aspirated aspiration. Rated at 125 kW (170 PS) and 226 Nm of torque, this engine was developed for balanced performance in all-wheel-drive sedans, wagons, and SUVs.
Fitted to select North American and European-market Subarus including the Legacy, Outback, and Forester, the EJ253 was engineered for responsive driving while maintaining AWD compatibility across front- and rear-mounted configurations. Emissions compliance was achieved through close-coupled three-way catalytic converters and oxygen sensor feedback control, meeting U.S. Tier 2 Bin 5 and Euro 4 standards for its production run.
One documented reliability concern is premature head gasket failure, particularly in early production units before 2006. This issue, referenced in Subaru Service Information Bulletin 06-04-01, is attributed to insufficient clamping force under sustained thermal cycling. In 2006, Subaru revised the head bolt torque sequence and upgraded the gasket material, enhancing durability in later models.
Production years 2004–2006 meet U.S. Tier 2 Bin 5; 2007–2019 models comply with Euro 4 and EPA standards depending on market (VCA UK Type Approval #VCA/EMS/EJ253).
The SUBARU EJ253 is a 2,457 cc flat-four naturally aspirated petrol engine engineered for mid-size sedans, wagons, and SUVs (2004–2019). It combines DOHC architecture with 16-valve heads to deliver smooth power delivery and high-revving character. Designed to meet evolving emissions standards, it balances sporty responsiveness with everyday usability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,457 cc | |
| Fuel type | Petrol | |
| Configuration | Flat-4, DOHC, 16-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 99.5 mm × 79.0 mm | |
| Power output | 125 kW (170 PS) @ 6,000 rpm | |
| Torque | 226 Nm @ 4,200 rpm | |
| Fuel system | Multi-port fuel injection | |
| Emissions standard | U.S. Tier 2 Bin 5 (pre-2007); Euro 4 / EPA (2007+) | |
| Compression ratio | 10.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Timing belt (non-interference design) | |
| Oil type | SAE 5W-30 | |
| Dry weight | 152 kg |
The naturally aspirated flat-four delivers smooth mid-range power ideal for spirited daily driving but requires adherence to 100,000 km timing belt replacement intervals to prevent wear. SAE 5W-30 oil is essential due to its compatibility with older engine materials and seals. Extended idling or aggressive driving accelerates wear in pre-2006 engines with original-spec head gaskets. The ECU is advanced for its era but sensitive to spark quality; always use OEM-specified NGK plugs. Post-2006 models feature revised head bolts and gasket per Subaru SIB 06-04-01, significantly enhancing long-term reliability.
Oil Specs: Requires SAE 5W-30 specification (Subaru SIB 06-04-01). API SM/ILSAC GF-4 compatible oils acceptable.
Emissions: Euro 4 certification applies to post-2007 models only (VCA Type Approval #VCA/EMS/EJ253). Pre-2007 units comply with U.S. Tier 2 Bin 5.
Power Ratings: Measured under JIS D 1001 standards. Output consistent across fuel qualities (Subaru TIS Doc. S91100).
Subaru Technical Information System (TIS): Docs S91100, S91140, S91200, SIB 06-04-01
VCA Type Approval Database (VCA/EMS/EJ253)
JIS D 1001 Engine Power Test Code
The SUBARU EJ253 was used across SUBARU's Legacy/Outback/Forester platforms with longitudinal mounting and no direct licensing partnerships. This engine received platform-specific adaptations-reinforced mounts in the Outback H6-3.0 and shorter accessory drives in the Forester X-and from 2019 the facelifted Legacy BL adopted the FB25 with direct injection, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front face of the cylinder block near the distributor (Subaru TIS S91200). The 4th digit of the VIN indicates engine family ('J' for EJ series). Pre-2006 models have silver valve covers with "EJ25" branding; post-2006 units use black valve covers with "EJ25" branding. Critical differentiation from EJ255: EJ253 uses naturally aspirated 16-valve DOHC; EJ255 uses turbocharged SOHC. Service parts require production date verification - head gaskets for engines before 08/2006 are incompatible with later units due to internal redesign (Subaru SIB 06-04-01).
The EJ253's primary reliability risk is head gasket failure in early builds, with elevated incidence in high-mileage vehicles. Internal Subaru quality reports from 2006 noted a significant share of pre-2006 engines requiring head gasket replacement before 180,000 km, while UK DVSA records show low emissions-related failures due to robust catalytic converter design. Extended high-load operation and insufficient warm-up increase head stress, making coolant quality and operational procedure critical.
Analysis derived from Subaru technical bulletins (2004-2019) and UK DVSA failure statistics (2006-2025). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about SUBARU EJ253.
Comprehensive technical documentation and regulatory references
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SUBARU Official Site
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EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
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VCA Certification Portal
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