The SUBARU FB20C is a 1,995 cc, flat-four naturally aspirated petrol engine produced between 2012 and 2023. It features DOHC, 16-valve configuration with AVCS (Active Valve Control System) on both intake and exhaust cams, delivering 110 kW (150 PS) and 196 Nm of torque. Its horizontally opposed layout provides low center of gravity and balanced performance across mainstream platforms.
Fitted to the XV/Crosstrek, Forester, and Legacy series, the FB20C was engineered for responsive everyday driving and all-weather reliability in Subaru's global lineup. Emissions compliance was achieved through exhaust gas recirculation (EGR), catalytic converter, and closed-loop fuel control, enabling Euro 5 and US Tier 2 standards depending on market.
One documented concern is head gasket degradation under sustained high load or improper cooling system maintenance. This issue, highlighted in Subaru Service Information Bulletin 13-04-02, often led to coolant loss and compression leakage. In response, Subaru issued revised cylinder head machining procedures and recommended use of multi-layer steel (MLS) gaskets during repairs.
Production years 2012–2023 meet Euro 5 and US Tier 2 emissions standards depending on market (VCA UK Type Approval #VCA/EMS/3480).
The SUBARU FB20C is a 1,995 cc flat-four naturally aspirated petrol engine engineered for compact, mid-size, and SUV applications (2012–2023). It combines Subaru's signature boxer layout with DOHC valvetrain and dual AVCS technology to deliver refined power delivery and mechanical balance. Designed to meet evolving emissions standards, it balances everyday performance with regulatory compliance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,995 cc | |
| Fuel type | Petrol | |
| Configuration | Flat-4, DOHC, 16-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 84.0 mm × 90.0 mm | |
| Power output | 110 kW (150 PS) @ 6,200 rpm | |
| Torque | 196 Nm @ 4,200 rpm | |
| Fuel system | Multi-point fuel injection (MPFI) with dual AVCS | |
| Emissions standard | Euro 5, US Tier 2 (market-dependent) | |
| Compression ratio | 10.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Single-row timing chain | |
| Oil type | SAE 0W-20 (API SN) | |
| Dry weight | 130 kg |
The flat-four design provides inherent balance and smoothness ideal for daily driving but requires strict adherence to 15,000 km oil change intervals to maintain chain longevity and lifter function. Use of API SN-rated oil is critical due to its formulation supporting hydraulic lifters and timing chain lubrication. Cooling system maintenance is essential to prevent overheating and head gasket failure; use of correct coolant mix (HOAT-based) and regular flushes are recommended. Pre-2014 models should follow revised head gasket installation procedures per Subaru SIB 13-04-02 if experiencing compression loss. Engines used in high-mileage applications require valve clearance inspection every 60,000 km.
Oil Specs: Requires API SN specification oils (Subaru Owner's Manual 12-23). Non-detergent or lower-grade oils increase wear risk.
Emissions: Euro 5 and US Tier 2 certification applies to production years (2012–2023) (VCA Type Approval #VCA/EMS/3480). Market-specific variations exist.
Power Ratings: Measured under SAE J1349 standards. Output consistent across fuel qualities meeting ASTM D4814.
Subaru Technical Information System (TIS): Docs A20000, A20300, SIB 13-04-02
Subaru EPC and Parts Catalogue: E-FB20C Series
VCA Type Approval Database (VCA/EMS/3480)
SAE International: J1349 Engine Power Certification Standards
The SUBARU FB20C was used across SUBARU's XV/Crosstrek/Forester/Legacy platform with longitudinal mounting. This engine received platform-specific adaptations-base trims in hatchbacks and wagons-and from 2023 the facelifted Legacy LCI adopted the FA24 variant with updated architecture, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the left-side engine block near the transmission bellhousing (Subaru TIS A20900). The 5th digit of the VIN indicates engine family ('F' for FB series). All FB20C units have silver valve covers with "FB20" branding and AVCS solenoids on both cam covers. Critical differentiation from FA24: Original FB20C uses 2.0L displacement with smaller bore, while FA24 features 2.4L and DOHC configuration. Service parts require production date verification - head gaskets before 06/2014 are prone to failure and should be replaced with post-revision MLS units per Subaru SIB 13-04-02.
The FB20C's primary reliability risk is head gasket degradation on pre-2014 builds, with elevated incidence in mixed driving conditions. Internal Subaru quality reports from 2013 indicated a significant number of pre-upgrade heads requiring replacement before 100,000 km, while UK DVSA records show coolant-related failures were common in neglected examples. Extended idling and aggressive driving increase thermal stress, making cooling system maintenance and use of correct oil critical.
Analysis derived from Subaru technical bulletins (2012–2023) and UK DVSA failure statistics (2024–2025). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about SUBARU FB20C.
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.
