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Subaru FB20 Engine - Replacement Cost, Problems & CompatibilityProblems & Compatibility
The Subaru FB20 is a 2.0-litre naturally aspirated boxer engine that replaced the EJ20 across the range, featuring direct injection, improved fuel efficiency, and a timing chain rather than a belt. Reconditioned units from £1,800 - the modern Subaru engine found in Impreza, XV and Forester models.
Supply & Fit Available
12-Month Warranty
Nationwide Delivery
100+ Suppliers
Used from
£1,200
Reconditioned from
£1,800
Rebuilt from
£2,800
GB
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Key Specs
Subaru FB20 - Specifications at a Glance
Engine Code
FB20 (FB20B, FB20D)
Fuel
Petrol
Configuration
2.0L naturally aspirated flat-four (Boxer), DOHC 16-valve, direct injection (FB20D)
Power Output(s)
148-150 hp (depending on market and revision)
Years Produced
2010-present (UK: 2012-present)
UK Models Fitted
3 models - full list in Compatibility below
2025 UK Replacement Requests
[Not in proprietary data - see compatibility demand]
Replaced
EJ20 (2.0L)
Replaced By
- (current engine; CB18 on some newer models)
Most Common Failure
Oil consumption / direct injection carbon buildup
Reconditioned Price Range
£1,800-£2,800 supply-only
Vetted UK specialists for FB20 replacements
Minimum 12-month warranty on reconditioned and rebuilt options
Fitted To
Which Subaru Models Use the FB20-
The FB20 is Subaru's modern 2.0-litre naturally aspirated boxer engine, introduced in 2010 and progressively replacing the EJ20 across the range. It was the first Subaru engine to feature a timing chain instead of a belt.
| Model | Generation/Chassis | Badge(s) | Years | Link |
|---|---|---|---|---|
 Subaru Impreza | GJ/GP (2012-2016) | 2.0i, 2.0i-S | 2012-2016 | |
| Subaru XV | GP (2012-2017) | 2.0i, 2.0i-SE | 2012-2017 | |
| Subaru XV | GT (2017-present) | 2.0i, 2.0i-SE, e-Boxer | 2017-present | |
| Subaru Forester | SJ (2013-2018) | 2.0i, 2.0i-L, 2.0i-S | 2013-2018 | |
| Subaru Forester | SK (2018-present) | 2.0i, e-Boxer | 2018-present |
02
Subaru XV
03
Subaru XV
04
Subaru Forester
05
Subaru Forester
CROSS-BRAND
FB20 is documented across 5 BMW applications spanning Subaru Impreza, Subaru XV, Subaru Forester. Registration lookup confirms the exact suffix before quotes are sent.
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Not sure which engine your car has- Enter your registration above - we'll confirm your exact FB20 fitment before any quotes are sent.
Prices
Subaru FB20 Engine Replacement Cost (UK)
Condition | Supply Only | Fitted (Independent Specialist) | Typical Warranty |
|---|---|---|---|
Used | £1,200-£1,800 | £1,900-£2,700 | 3-6 months |
Reconditioned | £1,800-£2,800 | £2,600-£3,700 | 12-24 months |
Rebuilt | £2,800-£4,000 | £3,700-£5,000 | 12-24 months |
All . Fitted = supply price + labour band below.
Labour Guide
Fitting an FB20 typically takes 8-12 hours at £65-£85/hr (independent Subaru specialist) - confirm exact labour when comparing quotes.
Price Factors
What genuinely moves the price for THIS engine: whether the engine is the later direct-injection FB20D (2017+) or the earlier port-injection FB20B - the FB20D is more expensive to source and repair. Whether the engine includes the CVT (Lineartronic) or manual transmission ancillaries also affects the final price. See our full reconditioned engine cost guide.
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Common Problems
Subaru FB20 Engine Problems - What Actually Fails
Every engine has its weak points. Here are the known issues with the FB20, based on real-world data and verified failure patterns.
Verified issue focus: Oil consumption / direct injection carbon buildup.
The FB20 improved significantly over its production run. FB20D (2017+) with direct injection is more fuel-efficient but more prone to carbon buildup. Later piston ring revisions (post-2015) reduced oil consumption issues. The FB20 is generally more reliable than the EJ20, especially with the timing chain eliminating belt failure risk .
Compare rebuilt FB20 prices with the failures already addressed
Engine Variants
FB20 Variants - Which One Is in Your Car-
INTRO: While FB20 is the family name, there are two primary variants - the earlier port-injection FB20B and the later direct-injection FB20D. The differences matter when buying a replacement. ### FB20B - 2010-2016 (port injection) - Fitted to: Subaru Impreza GJ/GP (2012-2016), Subaru XV GP (2012-2017), Subaru Forester SJ (2013-2016) - Key technical difference: Naturally aspirated, DOHC, 16-valve. Port injection (fuel injectors in the intake manifold). Compression ratio: 10.5:1. Power: 148 hp (110 kW) at 6,200 rpm, 196 Nm at 4,200 rpm. Timing chain (no belt). Single AVCS (variable valve timing on intake only). Uses conventional multi-port fuel injection. - Sub-code-specific failure note: Oil consumption is the primary issue on this variant - early engines (2012-2014) are more prone to piston ring wear. - Interchange note: Direct swap with FB20D is not possible without significant ECU and wiring changes (fuel system, injectors, high-pressure pump). Ensure the replacement matches your engine's injection type. ### FB20D - 2017-present (direct injection) - Fitted to: Subaru XV GT (2017-present), Subaru Forester SK (2018-present), Subaru Impreza (2017-present, some markets) - Key technical difference: Naturally aspirated, DOHC, 16-valve. Direct injection (fuel injectors directly in the cylinder head). Compression ratio: 12.5:1 (higher than FB20B). Power: 150 hp (110 kW) at 6,200 rpm, 194 Nm at 4,200 rpm. Dual AVCS (variable intake and exhaust valve timing). Features a high-pressure fuel pump. - Sub-code-specific failure note: Carbon buildup on intake valves is the primary issue - a known downside of direct injection. Oil consumption is less common than on FB20B. - Interchange note: Not a straight swap with FB20B - fuel system, ECU, wiring loom, and high-pressure pump differ completely. Use the correct variant for your model year. ### FB20 e-Boxer (mild hybrid) - 2018-present - Fitted to: Subaru XV e-Boxer, Subaru Forester e-Boxer - Key technical difference: FB20D with a mild hybrid system (12V lithium-ion battery and integrated starter-generator). The engine itself is identical to FB20D mechanically, but the hybrid ancillaries and ECU are different. - Sub-code-specific failure note: Same as FB20D - carbon buildup. Hybrid-specific components (battery, motor) have their own separate failure modes (not covered on this page). - Interchange note: Not a direct swap with non-hybrid FB20D without the full hybrid system. Only replace with another e-Boxer engine.
The engine code is stamped on the top of the engine block, near the bellhousing mating face. It's also listed on the V5C registration document. For FB20D, look for the high-pressure fuel pump on the top of the engine - a clear visual indicator of direct injection. Enter your registration above if you're unsure - we'll confirm your exact FB20 variant before any quotes are sent.
Easily Confused
EJ20
- the 2.0-litre boxer that powered Subarus from 1989 until the FB20 replaced it. The EJ20 used a timing belt (interference), while the FB20 uses a timing chain. The FB20 is significantly more fuel-efficient and cleaner-running.
Alternative / Next-Gen Code
CB18
- the 1.8-litre turbocharged boxer introduced in 2020 for the Levorg and some Japanese models. Not yet widely available in the UK, but represents the next generation of Subaru boxer engines with improved efficiency and mild-hybrid integration.
Related JLR Variants
FB25
- the 2.5-litre naturally aspirated variant of the FB family. Used in the Subaru Outback, Forester (North America), and Legacy. The FB25 has more torque but similar fuel consumption to the FB20.
Confirm the exact FB20 fitment
The engine code is stamped on the top of the engine block, near the bellhousing mating face. It's also listed on the V5C registration document. For FB20D, look for the high-pressure fuel pump on the top of the engine - a clear visual indicator of direct injection. Enter your registration above if you're unsure - we'll confirm your exact FB20 variant before any quotes are sent.
Buying Guide
Buying a Replacement FB20 - What to Choose
Choosing the right replacement route depends on your budget, risk tolerance, and ownership goals. Here's a breakdown of your options.
Used:
A used FB20 makes sense if you're replacing a high-mileage unit in a lower-value car (e.g., an early Impreza or XV). However, be aware of oil consumption (FB20B) and carbon buildup (FB20D). A used engine with documented service history and low mileage (under 60k) is a reasonable bet. Avoid early FB20B (2012-2014) with no oil consumption fix applied.
Reconditioned:
A proper FB20 recon addresses the known weak points: for FB20B, new piston rings with improved design (to solve oil consumption); for FB20D, a thorough carbon cleaning of intake valves. Both variants get new timing chain tensioner, new water pump, and new gaskets/seals. A 12-month warranty is standard. Reconditioned units are the sweet spot for most owners - you get reliability upgrades without a full rebuild.
Rebuilt:
A full FB20 rebuild is justified when you own a high-value example (e.g., a well-specced Forester or XV) and want the engine to last another 150,000+ miles. For FB20B, forged pistons can be fitted to eliminate oil consumption permanently. For FB20D, a rebuild includes new valve guides and seals to reduce carbon buildup. Budget £2,800-£4,000 for a quality rebuild.
Supply & Fit Line:
All of our vetted UK Subaru specialists offer supply-only or full supply-and-fit - nationwide delivery and recovery available, with warranties that cover both parts and labour.
Vehicle Value Note:
The FB20 sits in mid-range Subaru models - XV values range from £6,000-£16,000; Forester £8,000-£22,000; Impreza £4,000-£12,000 depending on year and mileage. A reconditioned FB20 at £1,800-£2,800 represents 15-35% of vehicle value - generally viable. For a high-mileage (£4,000-£6,000) early Impreza or XV, a full rebuild at £4,000 may approach 60-100% of vehicle value - evaluate the car's overall condition before committing. .
Compare FB20 Engine Prices Now --- **
Related Engines
Engines Related to the Subaru FB20
Explore engines that are closely related to the Subaru FB20, including its predecessor, successor, and key family variants.
Predecessor
EJ20
- the 2.0-litre boxer that powered Subarus from 1989 until the FB20 replaced it. The EJ20 used a timing belt (interference), while the FB20 uses a timing chain. The FB20 is significantly more fuel-efficient and cleaner-running.
Successor
CB18
- the 1.8-litre turbocharged boxer introduced in 2020 for the Levorg and some Japanese models. Not yet widely available in the UK, but represents the next generation of Subaru boxer engines with improved efficiency and mild-hybrid integration.
Sibling
FB25
- the 2.5-litre naturally aspirated variant of the FB family. Used in the Subaru Outback, Forester (North America), and Legacy. The FB25 has more torque but similar fuel consumption to the FB20.
Sibling
FA20
- the 2.0-litre direct-injection turbo used in the Subaru BRZ / Toyota GT86 and the WRX (2015+). Though displacement is the same, the FA20 is a completely different engine family - it uses a different block, has a turbo (or higher compression for the BRZ), and is not interchangeable with the FB20.
FAQ
Subaru FB20Frequently Asked Questions
Question 1How much does a Subaru FB20 engine replacement cost-
A reconditioned FB20 supply-only costs £1,800-£2,800, with fitted prices from £2,600-£3,700. Used units start from £1,200 supply-only. Rebuilt engines cost £2,800-£4,000 supply-only.
- Used units start from £1,200 supply-only.
- Rebuilt engines cost £2,800-£4,000 supply-only.
Question 2What are the most common FB20 engine problems-
The FB20 suffers from oil consumption (FB20B, especially 2012-2014), carbon buildup on intake valves (FB20D direct-injection, 2017+), and timing chain tensioner wear (100k-150k miles). Oil consumption can require piston ring replacement (£1,500-£3,000). Carbon cleaning costs £300-£600. Timing chain tensioner replacement £400-£800.
- Oil consumption can require piston ring replacement (£1,500-£3,000).
- Carbon cleaning costs £300-£600.
- Timing chain tensioner replacement £400-£800.
Question 3Which Subaru models use the FB20 engine-
The FB20 is fitted to the Subaru Impreza (2012-2016), Subaru XV (2012-present), and Subaru Forester (2013-present) in the UK. The FB20B is in pre-2017 models. The FB20D is in 2017+ models with direct injection. e-Boxer variants use the FB20D with mild-hybrid system.
- The FB20B is in pre-2017 models.
- The FB20D is in 2017+ models with direct injection.
- e-Boxer variants use the FB20D with mild-hybrid system.
Question 4Should I buy a used or reconditioned FB20-
A reconditioned FB20 is the safer choice - it includes improved piston rings (for oil consumption on FB20B) and a thorough carbon clean (for FB20D), plus a 12-month warranty. Used FB20s are acceptable if low-mileage and with service history. Avoid early FB20B (2012-2014) without oil consumption fix.
- Used FB20s are acceptable if low-mileage and with service history.
- Avoid early FB20B (2012-2014) without oil consumption fix.
Question 5What’s the difference between FB20 and EJ20-
The FB20 replaces the EJ20 - it has a timing chain (no belt replacement), improved fuel economy, and lower emissions. The FB20 is also quieter and smoother, but early FB20B units suffered oil consumption, which the EJ20 didn’t have as severely. See the EJ20 page for details
- The FB20 is more modern but not a direct swap into an EJ20 car.
Question 6How long does an FB20 engine last-
With regular maintenance (oil changes every 6k miles), an FB20 can exceed 150,000 miles. Oil consumption may appear around 60k-120k miles. Carbon buildup on FB20D can be managed with regular cleaning. Timing chain tensioner may need replacement around 100k-150k miles.
- Oil consumption may appear around 60k-120k miles.
- Carbon buildup on FB20D can be managed with regular cleaning.
- Timing chain tensioner may need replacement around 100k-150k miles.
Compare Subaru FB20 Engine Prices Today
Get free, no-obligation FB20 engine quotes tailored to your exact variant (FB20B or FB20D) and model. Our registration lookup confirms fitment before any quotes are sent, so you only hear from specialists who can actually supply the right unit. With reconditioned FB20 units from around £1,800, comparing takes two minutes and could save four figures.
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Vetted UK specialists for FB20 replacements
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Minimum 12-month warranty on reconditioned and rebuilt options
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