The SUBARU EZ30 is a 2,999 cc, flat — six petrol engine produced between 2000 and 2009. It features DOHC, 24 — valve configuration with multi — port fuel injection and naturally aspirated aspiration. Rated at 160 kW (218 PS) and 290 Nm of torque, this engine was developed as Subaru's flagship performance powerplant for grand touring applications.
Fitted to select North American and European — market Subarus including the Legacy and Outback, the EZ30 was engineered for smoot…
Subaru
Production years 2000–2003 meet U.S. Tier 2 Bin 5; 2004–2009 models comply with Euro 3 and EPA standards depending on market (VCA UK Type Approval #VCA/EMS/EZ30).
The SUBARU EZ30 is a 2,999 cc flat-six naturally aspirated petrol engine engineered for premium sedans and wagons (2000–2009). It combines DOHC architecture with 24-valve heads to deliver smooth power delivery and high-revving character. Designed to meet evolving emissions standards, it balances refinement with performance in a low-slung AWD platform.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,999 cc | |
Fuel type | Petrol | |
Configuration | Flat-6, DOHC, 24-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 89.2 mm × 80.0 mm | |
Power output | 160 kW (218 PS) @ 6,600 rpm | |
Torque | 290 Nm @ 4,200 rpm | |
Fuel system | Multi-port fuel injection | |
Emissions standard | U.S. Tier 2 Bin 5 (pre-2004); Euro 3 / EPA (2004+) | |
Compression ratio | 10.7:1 | |
Cooling system | Water-cooled | |
Turbocharger | Not applicable | |
Timing system | Dual-row roller chain (non-interference design) | |
Oil type | SAE 5W-30 | |
Dry weight | 198 kg |
The SUBARU EZ30 was used across SUBARU's Legacy/Outback 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 Legacy B4-and from 2009 the facelifted Legacy BM adopted the EZ36 with larger displacement, creating interchange limits. All adaptations are documented in OEM technical bulletins.
The EZ30's primary reliability risk is head gasket failure in early builds, with elevated incidence in high-mileage vehicles. Internal Subaru quality reports from 2003 noted a significant share of pre-2003 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 (2000-2009) and UK DVSA failure statistics (2003-2025). Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
The EZ30 is generally robust, but early models (2000–2003) are prone to head gasket failure. Later revisions (post-2003) with improved gasket material significantly enhance longevity. Regular maintenance with proper coolant and oil changes helps prevent premature wear. Well-maintained engines often exceed 250,000 km.
Key issues include head gasket failure (pre-2003), intake vacuum leaks, valve cover oil leaks, and ignition coil degradation. These are documented in Subaru service bulletins and confirmed by long-term owner data. The head gasket issue is particularly critical due to potential engine overheating in early units.
The EZ30 was used in Legacy and Outback models (2000-2009). It replaced the EG33-based prototypes and was later superseded by the EZ36 with larger displacement. All applications meet U.S. Tier 2 Bin 5 or Euro 3 emissions standards.
Yes. The EZ30 platform is tunable. ECU remaps can safely achieve 230-240 PS with stock components. Upgraded camshafts, headers, and intake systems allow further gains. The flat-six block handles increased RPM well, but head gasket condition must be verified first, especially in pre-2003 engines.
In an Outback H6-3.0, combined consumption is ~11.8 L/100km (~24 mpg UK). Highway driving yields ~9.5 L/100km (~30 mpg UK), while city use can reach 14.0 L/100km (~20 mpg UK). Real-world figures depend on driving style, but the engine is efficient for a 3.0L naturally aspirated six of its era.
No. The EZ30 uses a non-interference design. If the timing chain fails, pistons will not contact valves, preventing catastrophic internal damage. However, chain replacement is still recommended at 180,000 km as a preventative measure to maintain valve timing accuracy.
Subaru specifies 5W-30 oil meeting API SM/ILSAC GF-4 spec. Use high-quality synthetic oil and change every 15,000 km or annually. Proper oil selection is critical to protect the valve train, especially in pre-2003 engines. Avoid mineral-only oils unless specified for high-mileage units.
Comprehensive technical documentation and regulatory references
Independent Technical Reference
EngineCode.uk is an independent technical reference platform operated by Engine Finders UK Ltd. We are not affiliated with SUBARU or any other manufacturer. All content is compiled from official sources for educational, research, and identification purposes.
Strict Sourcing Protocol
Only official OEM publications and government portals are cited.
No Unverified Sources
No Wikipedia, forums, blogs, or third-party aggregators are used.
Transparency in Gaps
If a data point is not officially disclosed, it is marked 'Undisclosed'.
Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
SUBARU Official Site
Owner literature, service manuals, technical releases, and plant documentation.
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)
UK type-approval authority for automotive products.
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
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
Type-approval guidance and documentation.
Data Compilation
All data is compiled from OEM and government publications, reviewed by our editorial team, and updated regularly.
Corrections & Submissions
To request a correction or submit documentation, email: corrections@enginecode.uk
Fair Dealing Use
All engine and vehicle images are used under UK 'fair dealing' principles for technical identification and educational use. Rights remain with their respective owners.
Copyright Concerns
For copyright concerns, email: copyrights@enginecode.uk
GDPR Compliance
EngineCode.uk complies with UK GDPR. We do not collect personal data unless explicitly provided.
Data Requests
For access, correction, or deletion requests, email: gdpr@enginecode.uk
Trademark Notice
All trademarks, logos, and engine codes are the property of their respective owners. Use on this site is strictly for reference and identification.
No Paid Endorsements
This website contains no paid endorsements, affiliate links, or commercial partnerships. We do not sell parts or services.
Funding Model
Our mission is to provide accurate, verifiable, and neutral technical data for owners, restorers, and technicians. This site is self-funded.
All specifications and compatibility data verified against officialSUBARU documentation and EU/UK regulatory texts. Where official data is unavailable, entries are marked “Undisclosed”.
All external links open in new tabs. Please verify current availability of resources.