The SUBARU FB24 is a 2,387 cc, flat — four petrol engine produced between 2019 and 2025. It features DOHC, 16 — valve configuration with direct fuel injection and naturally aspirated aspiration. Rated at 137 kW (186 PS) and 235 Nm of torque, this engine was developed for balanced performance in all — wheel — drive sedans, wagons, and SUVs.
Fitted to select North American and global — market Subarus including the Outback and Legacy, the FB24 was engineered for responsive drivin…
Production years 2019–2025 meet U.S. Tier 2 Bin 5 and EPA Tier 3 standards depending on market .
The SUBARU FB24 is a 2,387 cc flat-four naturally aspirated petrol engine engineered for mid-size sedans, wagons, and SUVs (2019–2025). It combines DOHC architecture with direct fuel injection to deliver smooth power delivery and high-revving character. Designed to meet evolving emissions standards, it balances sporty responsiveness with everyday usability.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,387 cc | |
Fuel type | Petrol | |
Configuration | Flat-4, DOHC, 16-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 94.0 mm × 86.0 mm | |
Power output | 137 kW (186 PS) @ 5,600 rpm | |
Torque | 235 Nm @ 4,400 rpm | |
Fuel system | Direct fuel injection (D-4S) | |
Emissions standard | U.S. Tier 2 Bin 5 / EPA Tier 3 | |
Compression ratio | 12.0:1 | |
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 | 154 kg |
The SUBARU FB24 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 Wilderness and shorter accessory drives in the Legacy Touring XT-and from 2025 the facelifted Outback will adopt the CB18 with turbocharging, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Engine Finders UK Ltd, which operates EngineCode.uk, can pass your enquiry to engine suppliers in the UK. The service is for vehicles in the United Kingdom, with UK delivery or fitting. This is a commercially connected service, and sending an enquiry does not confirm diagnosis or compatibility.
Diagnostic reminder: If a technician has recommended replacing the engine, you can send an enquiry to engine suppliers in the UK. Confirm the diagnosis first: an engine-code record does not diagnose a fault.
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 FB24 is generally robust, but early models (2019–2021) are prone to timing chain tensioner wear. Later revisions (post-2021) with improved oil rail design significantly enhance longevity. Regular oil changes with SAE 0W-20 spec oil and avoiding short trips help prevent premature wear. Well-maintained engines often exceed 200,000 km.
Key issues include timing chain tensioner wear (pre-2021), 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 tensioner issue is particularly critical due to oil starvation in early units.
The FB24 was used in Legacy and Outback models (2019-2025). It replaced the FB25-based prototypes and maintains continuity in naturally aspirated applications. All applications meet U.S. Tier 2 Bin 5 and EPA Tier 3 emissions standards.
Aftermarket ECU tuning is common on the FB24 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 2.4i, combined consumption is ~8.8 L/100km (~32 mpg UK). Highway driving yields ~7.5 L/100km (~38 mpg UK), while city use can reach 10.5 L/100km (~27 mpg UK). Real-world figures depend on driving style, but the engine is efficient for a 2.4L naturally aspirated four of its era.
No. The FB24 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 0W-20 oil meeting API SP/ILSAC GF-6 spec. Use high-quality synthetic oil and change every 15,000 km or annually. Proper oil selection is critical to protect the timing chain and direct injection system, especially in pre-2021 engines. Avoid higher viscosity oils unless retrofitted.
Comprehensive technical documentation and regulatory references
EngineCode.uk is operated by Engine Finders UK Ltd. It provides engine-reference information and an optional commercial enquiry service. It is not an official manufacturer website. Check the record's sources and confirm vehicle-specific details before relying on it for parts, repairs or replacement.
Our editorial standard prioritises relevant manufacturer documentation and official regulatory sources. The sources and verification status for a record should be checked alongside the data.
A statement is not verified merely because a source is listed. Where supporting evidence is missing or conflicting, the record should identify that limitation. Please report unsupported or inconsistent information.
Transparency in gaps
A missing or unverified value does not mean the manufacturer has withheld it. We distinguish information not yet verified, information not available to us, and information explicitly not disclosed by the source.
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.
Records are subject to review and correction. Source links, dates and verification notes should be read with the technical information. Our Editorial and Sourcing Policy explains our standards and review process.
Found an error or missing source? Report a problem with this page. Include the field or statement concerned and a supporting source if available. You can also email corrections@enginecode.uk.
Copyright and permissions
Images and other material may be protected by copyright. Attribution does not by itself grant permission to reuse material. If you believe material on this site infringes your rights, contact copyrights@enginecode.uk with the page URL and details of your claim. We will review the material and take appropriate action.
Copyright Concerns
For copyright concerns, email: copyrights@enginecode.uk
Our Privacy Policy explains how Engine Finders UK Ltd uses information from visits, vehicle lookups, enquiries and messages. Our Cookie Policy explains cookies and similar technologies and how to change your choices.
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.
Ownership and commercial services
EngineCode.uk is owned and operated by Engine Finders UK Ltd. Alongside our reference content, we offer an optional replacement-engine enquiry service through Engine Finders and may identify relevant services provided by businesses connected with us. These commercial connections are disclosed. Using an enquiry service is not required to read our reference content.
Engine Finders UK Ltd operates this website. Our optional enquiry service has a commercial purpose. Our Ownership and Commercial Disclosure explains the relationship between the reference website and that service. Participating suppliers pay a fee or subscription to participate on the network and receive quote requests.
Use this record as a starting point for identification. Specifications and vehicle applications may contain errors or omissions. Confirm the exact engine variant and compatibility using vehicle-specific documentation and a qualified supplier or technician.
All external links open in new tabs. Please verify current availability of resources.