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 .
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 | Refer to vehicle handbook / manufacturer specification | |
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.
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Field reports and technical service bulletins highlight component wear patterns under high-load operation. Adherence to manufacturer service intervals and approved fluid specifications is critical for long-term reliability.
Analysis derived from manufacturer technical service bulletins and industry workshop records. 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.
Aftermarket ECU tuning is common on the EZ30 platform, but increasing boost or altering engine parameters accelerates component wear, impacts emissions compliance, and may void vehicle warranties. Any modifications should be evaluated carefully by a qualified specialist.
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
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Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
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.
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