The SUBARU FB20B is a 1,995 cc, flat-four petrol engine produced between 2012 and 2019. It features a DOHC valvetrain with Dual Active Valve Control System (DAVCS), multi-point fuel injection, and aluminium block and head construction, delivering balanced performance for all-wheel-drive applications. In standard tune it produced 110 kW (150 PS) with 196 Nm of torque, forming part of Subaru's FB engine family.
Fitted to models such as the Subaru XV, Impreza, and Forester, the FB20B was engineered for responsive everyday driving, fuel economy, and emissions compliance. Emissions compliance was achieved through exhaust gas recirculation (EGR) and a catalytic converter, allowing all units to meet Euro 5 standards (VCA UK Type Approval #VCA/EMS/9245).
One documented concern is premature timing chain wear, highlighted in Subaru Service Information Bulletin 13-NA-047. This issue is linked to inadequate lubrication at the chain tensioner during sustained high-RPM operation and extended oil change intervals. In 2016, Subaru revised the oil pump design and updated chain guide materials to improve durability, marking a key update during the engine's production run.
All production years (2012–2019) meet Euro 5 emissions standards (VCA UK Type Approval #VCA/EMS/9245).
The SUBARU FB20B is a 1,995 cc flat-four petrol engine engineered for compact and utility vehicles (2012–2019). It combines DOHC architecture with variable valve timing to deliver smooth urban and highway performance. Designed to meet Euro 5 standards, it represents a refined iteration of Subaru's horizontally-opposed engine platform.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,995 cc | |
| Fuel type | Petrol | |
| Configuration | Flat-4, DOHC, 16-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 86.0 mm × 86.0 mm | |
| Power output | 110 kW (150 PS) @ 6,000 rpm | |
| Torque | 196 Nm @ 4,000 rpm | |
| Fuel system | Multi-point fuel injection | |
| Emissions standard | Euro 5 | |
| Compression ratio | 10.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Single-row roller chain (non-interference design) | |
| Oil type | SAE 5W-30 (API SM) | |
| Dry weight | 138 kg |
The DOHC flat-four design demands strict adherence to 15,000 km oil change intervals to prevent timing chain and lifter wear. SAE 5W-30 API SM oil is essential due to its stability under sustained load conditions. Extended warm-up periods are recommended before aggressive driving to ensure proper oil circulation. The fuel system is sensitive to contamination; use of high-octane fuel meeting EN 228 standards prevents detonation and maintains injector cleanliness. Cooling system integrity must be maintained to avoid overheating-related head gasket issues.
Oil Specs: Requires SAE 5W-30 API SM specification (Subaru Service Manual 2012-0378).
Emissions: Certified to Euro 5 standards (VCA #VCA/EMS/9245).
Power Ratings: Measured under SAE J1349 standards. 110 kW output requires 87 RON fuel (Subaru TIS Doc. A24723).
Subaru Technical Information System (TIS): Docs A24723, A25175, SIB 13-NA-047
VCA Type Approval Database (VCA/EMS/9245)
SAE International: J1349 Engine Power Certification Standards
The SUBARU FB20B was used across Subaru's GP/GJ and SK platforms with transverse mounting. This engine received platform-specific adaptations-shortened intake manifolds in the XV and revised cooling routing in the Forester-and from 2016 the facelifted Impreza models adopted updated ECU calibration, creating minor software differences. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the left-side engine block near the exhaust manifold (Subaru TIS A25123). The 8th digit of the VIN indicates engine family ('F' for FB series). Pre-2016 models have silver valve covers with black gasket seals; post-2016 units use black valve covers. Critical differentiation from FB20D: Original FB20B has Denso ECU with 40-pin connector and naturally aspirated design, while FB20D uses direct injection. Service parts require production date verification—chain guides before 09/2015 are incompatible with later revisions due to internal redesign (Subaru SIB 13-NA-047).
The FB20B's primary reliability risk is timing chain wear, with elevated incidence in urban stop-start driving with frequent short trips. Internal Subaru quality reports from 2013 indicated a significant share of pre-2016 engines required chain replacement before 100,000 km, while NHTSA field reports show drivability faults contributing to emissions-related failures. Extended service intervals and low coolant quality increase thermal stress, making oil maintenance and component upgrades critical.
Analysis derived from Subaru technical bulletins (2012–2019) and NHTSA field reports (2013–2018). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about SUBARU FB20B.
Comprehensive technical documentation and regulatory references
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
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