The Subaru EZ36D is a 3,649 cc, flat-six petrol engine produced between 2007 and 2019. It features a DOHC 24-valve configuration with multi-point fuel injection (MPFI) and delivers 191 kW (260 PS) in standard applications. Developed as the largest naturally aspirated engine in Subaru's lineup, it was engineered for smooth power delivery, refined operation, and balanced weight distribution in premium all-wheel-drive platforms.
Fitted to models such as the Outback 3.6R and Legacy 3.6R, the EZ36D was designed for drivers seeking strong linear acceleration and highway cruising refinement. Emissions compliance was achieved through exhaust gas recirculation (EGR), dual catalytic converters, and oxygen sensor feedback control, enabling it to meet U.S. EPA Tier 2 Bin 5 standards across its production run.
One documented reliability concern is timing chain guide wear under prolonged high-RPM operation, highlighted in Subaru Service Information Bulletin SSB-08-033. This issue is often associated with extended oil change intervals or use of non-specified lubricants. In 2010, Subaru revised the tensioner design and introduced updated polymer guides to improve durability.
Subaru
Production years 2007–2019 meet U.S. EPA Tier 2 Bin 5 standards; Canadian and European variants comply with equivalent national regulations (VCA UK Type Approval #VCA/EMS/2108).
The Subaru EZ36D is a 3,649 cc flat-six naturally aspirated engine engineered for mid-size and large applications (2007–2019). It combines Subaru's horizontally-opposed layout with MPFI to deliver smooth, vibration-free power delivery and mechanical refinement. Designed to meet Tier 2 Bin 5 emissions, it balances performance with longevity in diverse operating conditions.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 3,649 cc | |
| Fuel type | Petrol | |
| Configuration | Flat-6, DOHC, 24-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 92.0 mm × 91.0 mm | |
| Power output | 191 kW (260 PS) @ 6,000 rpm | |
| Torque | 350 Nm @ 4,400 rpm | |
| Fuel system | Multi-point fuel injection (MPFI) | |
| Emissions standard | U.S. EPA Tier 2 Bin 5 | |
| Compression ratio | 10.4:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Chain-driven (front-mounted, dual chains) | |
| Oil type | SAE 5W-30 (API SM) | |
| Dry weight | 182 kg |
The flat-six layout provides exceptional balance and low center of gravity ideal for all-wheel-drive dynamics but requires adherence to maintenance schedules to sustain longevity. SAE 5W-30 oil meeting API SM specifications is recommended for optimal lifter and camshaft lubrication. Oil changes should occur every 10,000 km or annually to prevent sludge buildup and timing chain wear. The interference design means valve damage will occur if the timing system fails. Valve clearance adjustments are required every 30,000 km using feeler gauges per factory procedure. Dual front-mounted chains demand inspection of both primary and secondary tensioners during major services.
Oil Specs: Requires API SM-rated 5W-30 oil (Subaru SIB SSB-08-033). Compatible with ILSAC GF-4 requirements.
Emissions: Tier 2 Bin 5 certification applies to all production years (VCA Type Approval #VCA/EMS/2108). No Euro 5-equivalent variants were produced.
Power Ratings: Measured under JIS D 1001 standards. Output achieved with 91 RON fuel and optimal ignition timing (Subaru TIS Doc. A36PERF).
Subaru Technical Information System (TIS): Docs A36EZ, A36FUEL, A36TIMING
VCA Type Approval Database (VCA/EMS/2108)
JIS D 1001: Internal combustion engine — Test code
The Subaru EZ36D was used across Subaru's Outback and Legacy platforms with longitudinal mounting and symmetrical all-wheel drive. This engine received platform-specific adaptations-reinforced transmission mounts in the Outback 3.6R and revised intake manifolds in the Legacy 3.6R-and from 2010 the updated Outback BL/BP Facelift models adopted improved timing chain guides and oil squirters, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front-left cylinder block near the exhaust manifold (Subaru TIS A36ID01). The 4th digit of the VIN indicates engine family ('E' for EZ series). Pre-2010 models have silver valve covers with ribbed rocker housings; post-2010 units use black valve covers with revised fastener layouts. Critical differentiation from EZ30D: EZ36D has larger displacement and different crankshaft. Service parts require production date verification - timing chain kits for pre-2010 models are incompatible with later revisions due to internal guide updates (Subaru SIB SSB-08-033).
The EZ36D's primary reliability risk is timing chain guide degradation on high-mileage engines, with elevated incidence in vehicles subjected to sustained highway driving. Internal Subaru engineering reports noted increased guide fracture rates beyond 150,000 km, while UK DVSA field data shows a notable share of noise-related MOT failures linked to chain rattle. Extended high-speed operation and delayed maintenance increase thermal stress, making oil quality and flush intervals critical.
Analysis derived from Subaru technical bulletins (2007-2019) and UK DVSA failure statistics (1995-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about SUBARU EZ36D.
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