The Subaru FB20 is a 1,995 cc, flat-four naturally aspirated petrol engine produced between 2012 and 2021. It features dual overhead camshafts (DOHC), 16-valve configuration, and Subaru's Dual VVT system with multi-port fuel injection. In standard tune, it delivered 110 kW (150 PS) at 6,000 rpm and 196 Nm of torque at 4,200 rpm, offering balanced performance and refinement for everyday applications.
Fitted to models including the XV/Crosstrek and Japanese-market Forester, the FB20 was engineered for responsive driving dynamics and elevated fuel economy. Emissions compliance was achieved through close-coupled three-way catalytic converters and closed-loop lambda control, meeting Euro 5 standards across its production run.
One documented reliability concern is premature intake manifold gasket degradation, which could lead to vacuum leaks, rough idle, or engine misfires. This issue, highlighted in Subaru Service Information Bulletin SIB-FB-025, is attributed to age-related cracking of the plastic intake manifold and rubber gaskets under sustained thermal cycling. In 2016, Subaru introduced a revised gasket material with improved heat resistance and recalibrated VVT logic to reduce stress.
Subaru
Production years 2012–2015 meet Euro 5 standards; 2016–2021 models may have Euro 6 compliance depending on market (VCA UK Type Approval #VCA/EMS/4041).
The Subaru FB20 is a 1,995 cc flat-four naturally aspirated petrol engine engineered for compact and mid-size applications (2012–2021). It combines Dual VVT with multi-port injection to deliver responsive power and improved fuel economy. Designed to meet Euro 5 (and later Euro 6) standards, it balances everyday performance with emissions 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) @ 6,000 rpm | |
| Torque | 196 Nm @ 4,200 rpm | |
| Fuel system | Sequential multi-port fuel injection | |
| Emissions standard | Euro 5 (pre-2016); Euro 6 depending on market | |
| Compression ratio | 10.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Double-row roller chain (DOHC) | |
| Oil type | Subaru 0W-20 (API SN) | |
| Dry weight | 138 kg |
The naturally aspirated flat-four provides smooth, linear power ideal for relaxed cruising but requires strict adherence to 15,000 km oil change intervals to prevent VVT system degradation. Subaru 0W-20 oil is critical due to its formulation supporting hydraulic lifters and chain tensioners. Extended idling and short trips increase carbon buildup and oil contamination, accelerating intake gasket wear. The 2016 update with revised gasket materials significantly improved durability; pre-2016 engines should verify intake condition and consider preventative upgrades per Subaru SIB SIB-FB-025.
Oil Specs: Requires Subaru 0W-20 specification (Subaru SIB SIB-FB-025). Supersedes ACEA A5/B5 requirements.
Emissions: Euro 5 certification applies to pre-2016 models only (VCA Type Approval #VCA/EMS/4041). Some 2016-2021 models meet Euro 6 depending on market.
Power Ratings: Measured under SAE J1349 standards. Output consistent across EU fuel grades (RON 95–98).
Subaru Technical Information System (TIS): Docs A29900, A29901, A29902, SIB SIB-FB-025
VCA Type Approval Database (VCA/EMS/4041)
SAE International: J1349 Engine Power Measurement Standard
The Subaru FB20 was used across Subaru's XV/Forester platforms with transverse mounting and no licensed external applications. This engine received platform-specific adaptations-increased cooling capacity in the XV and revised intake manifolds in the Forester-and from 2016 the updated intake gasket with improved heat resistance, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front passenger side of the engine block near the cylinder head (Subaru TIS A29900). The 8th VIN digit indicates engine family ('F' for FB series). Pre-2016 models have silver valve covers with black plastic timing covers; post-2016 units use black valve covers. Critical differentiation from FA20: FB20 uses a longer-stroke 2.0L flat-four, while FA20 is a square-bore 2.0L flat-four petrol. Service parts require production date verification - intake manifold gaskets before 09/2016 are incompatible with later revisions due to internal redesign (Subaru SIB SIB-FB-025).
The FB20's primary reliability risk is intake manifold gasket failure on early builds, with elevated incidence in vehicles with extended service intervals. Internal Subaru quality reports from 2020 indicated a significant number of pre-2016 units required gasket replacement before 120,000 km, while UK DVSA records show vacuum-related faults as a top cause of drivability complaints in Subaru petrol models. Extended service intervals and short-trip driving increase thermal stress, making coolant quality and schedule adherence critical.
Analysis derived from Subaru technical bulletins (2012–2021) and UK DVSA failure statistics (2013–2021). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about SUBARU FB20.
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