i3 REx Range Extender Engines
from £1,850 to £2,950
Rebuilt units from £1,850 · Common codes: B38A15R, B38A15R-2, B38A15R-3
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Get specialist quotes from UK BMW i Series EV & hybrid experts. Compare electric motor & hybrid system solutions for i3, i4, iX & i8. Find UK EV specialists.
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12-Month Warranty
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i8 Hybrid Petrol Engines
from £2,400 to £4,200
Rebuilt units from £2,400 · Common codes: B38A15T0, B38A15T0-2
i Series Pure Electric Drive Units
from £2,150 to £4,800
Rebuilt units from £2,150 · Common codes: EM100, EM100-2, EM200, EM200-2, EM200-3
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Supply & fit available - parts and labour from vetted specialistsInstant engine replacement quote - 100% free, no obligationEngine replacement near me - UK-wide specialist networkCompare reconditioned, rebuilt & used engine pricesSupply & fit available - parts and labour from vetted specialistsHow It Works
3 Simple Steps3 Simple Stepsto Finding the Best BMW i Series Replacement Engineto Finding the Best BMW i Series Replacement Engine
12-Month Warranty
Supply & Fit Available
Nationwide Delivery
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Most replacements completed within 3-5 days.
Live UK Engine Market Data
What Are UK Drivers Paying for BMW i Series Engine Replacement
The table below shows typical UK rebuilt engine costs across BMW i Series variants, covering documented failure causes, chassis codes, engine codes, fuel types and battery sizes based on current market data.
Average Market Prices
↻ Last updated: 4 Aug 26, 9:26
Customer Reviews
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Rated 4.8 out of 5 by 1,081 verified customers who sourced reconditioned and used BMW i Series engines through EngineMarket.
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Variants We Cover
BMW i Series Engine ReplacementAll Variants Covered
i3 60Ah
EM100 Electric
Rebuilt Engines: £2,500-£4,500
i3 94Ah
EM100-2 Electric
Rebuilt Engines: £2,800-£4,800
i3 120Ah
EM200 Electric
Rebuilt Engines: £3,000-£5,500
i3 REx 60Ah
B38A15R Petrol
Rebuilt Engines: £1,850-£2,950
i3 REx 94Ah
B38A15R-2 Petrol
Rebuilt Engines: £1,900-£3,100
i3 REx 120Ah
B38A15R-3 Petrol
Rebuilt Engines: £2,000-£3,300
i8 Coupe
B38A15T0 Petrol
Rebuilt Engines: £2,400-£4,200
i8 Coupe Facelift
B38A15T0-2 Petrol
Rebuilt Engines: £2,500-£4,500
i8 Roadster
B38A15T0-2 Petrol
Rebuilt Engines: £2,600-£4,700
i4 eDrive40
EM200-2 Electric
Rebuilt Engines: £3,200-£5,800
i4 M50
EM200-3 Electric
Rebuilt Engines: £3,800-£6,800
iX xDrive50
EM300-2 Electric
Rebuilt Engines: £3,600-£6,500
Not sure which variant your BMW i Series is- Enter your registration number above - we'll identify the exact sub-model, engine code and compatible replacement options instantly.
i Series
Engine Codes
BMW i Series Engine CodesFull Technical Specifications & Replacement Guide
Every engine code fitted to the BMW i Series across all generations, with technical specs, compatible variants and trims, known failure points, and average rebuilt prices from UK specialists. Select any engine code to compare quotes.
Petrol Engines
Extracted from detailed petrol and performance engine families across BMW i Series variants.
B38A15R - 0.6L Petrol (Range Extender)
Main replacement demand comes from timing-chain, cooling-system and performance thermal-management faults.
Compatible variants
i3 REx 60Ahi3 REx 60Ah Mega Worldi3 REx 60Ah Giga Worldi3 REx 60Ah Tera World
Avg. rebuilt price
£1,850 - £2,950
Supply only
Technical specifications
- Fuel type
- Petrol
- Engine size
- 0.6L
- Power output
- 34 hp
- Years fitted
- 2014-2022
Common failures
- ●Main replacement demand comes from timing-chain, cooling-system and performance thermal-management faults.
- ●Confirm exact engine code and fitment before ordering.
- ●Ask for warranty and supply & fit terms.
Not sure which engine code?
Can’t find your engine code- Enter your registration number above - we’ll instantly identify the exact unit, its technical specifications, and live replacement prices from UK BMW i Series engine specialists. Every rebuilt engine comes with a minimum 12-month unlimited mileage warranty.
i Series
Common Problems
BMW i Series Engine Problems - What It Costs to Fix & When Replacement Makes Sense
The BMW i Series electrified range - from the pioneering i3 to the hybrid i8 - has distinct failure patterns across its range extender petrol units, plug-in hybrid powertrains, and pure electric drive systems. The B38A15R range extender and B38A15T0 hybrid engine share some conventional engine failure modes, while EM-series drive units face bearing and...
BMW i3 REx Range Extender Carbon Buildup - Why B38A15R Generators Lose Output
BMW i3 REx Range Extender Carbon Buildup
Most affected vehicles
BMW i3 REx 60Ah94Ah
BMW i3 REx 60Ah, 94Ah, 120Ah (2014-2022, B38A15R, B38A15R-2, B38A15R-3)
Failure mileage range
30,000-60,000 miles
Typical failure window
Root cause
The 647cc two-cylinder range extender engine runs infrequently and often at low load, causing carbon deposits to accumulate on intake valves and injectors. This restricts airflow, reduces generator output, and can trigger emissions faults.
Repair options & estimated costs (UK ranges)
| Repair tier | Dealer price | Specialist price | What it involves | Longevity / suitability |
|---|---|---|---|---|
| Minor - Carbon Cleaning Service | £450 - £800 | £250 - £450 | Walnut blasting or chemical cleaning of intake valves and injector servicing | 20,000-30,000 miles; suitable if caught before output loss |
| Full Replacement - Rebuilt Range Extender Engine | £3,500 - £5,500 | £1,850 - £2,950 | Supply and fit of rebuilt B38A15R unit with cleaned intake system and new injectors | 60,000+ miles; only option if severe carbon has caused ring or valve damage |
Our recommendation
If your i3 REx is showing reduced generator output or rough running during range extender operation, book a carbon cleaning service immediately - it costs £250-£450 at a specialist and typically restores full performance. Ignoring carbon buildup can lead to valve damage and full engine replacement, which is four times the cost. On a 2015-2018 i3 REx worth £6,000-£10,000, the preventative cleaning makes clear financial sense.
Compare rebuilt B38A15R range extender prices for your BMW i3 RExReplacement Engine Options
BMW i Series Engine TypesOptions, Costs & What to Expect
Every engine type for your BMW i Series is available through our UK network, with typical price ranges based on your exact variant, engine code and budget.
BMW i Series Reconditioned Engines (Recon)£2,200 - £5,800((supply only))
BMW i Series Rebuilt Engines£2,500 - £6,200((supply only))
BMW i Series Used Engines£1,200 - £3,500((supply only))
BMW i Series Remanufactured Engines£2,800 - £6,500((supply only))
BMW i Series Refurbished Engines£1,600 - £3,800((supply only))
Compare BMW i Series engine prices with vetted UK suppliers
All engine types include a minimum 12-month unlimited mileage warranty when sourced through EngineMarket. Prices are typical UK market ranges based on historical quote data from our network and depend on exact engine code, variant, mileage and supplier. Use our free comparison tool above - enter your registration to get tailored quotes for your specific BMW i Series within hours.
Engine Sizes
BMW i Series Engines by SizeFind the Right Displacement for Your Variant
Every displacement fitted to the BMW i Series is listed below, with compatible engine codes, years and common failure notes.
The 647cc two-cylinder petrol engine serves exclusively as a range extender (REx) in the i3, never driving the wheels directly. Derived from the BMW C600 scooter, this lightweight auxiliary power unit generates electricity to charge the battery pack when depleted, adding approximately 40-80 miles of additional range depending on driving conditions . The REx option was introduced in 2014 for the 60Ah i3 and continued through to the 120Ah model until 2022 in European markets .
⚙
Engine Code(s)
B38A15R, B38A15R-2, B38A15R-3
▣
Compatible Models (UK)
i3 REx 60Ah (2014-2016), i3 REx 94Ah (2016-2018), i3 REx 120Ah
ϟ
Power output
Verified by registration
△
Common Failure Points
Carbon buildup on intake valves, generator bearing failure (rattling noise), injector fouling from infrequent use
Production Years: 2018-2022
Get quotes for BMW i Series 0.6L petrol enginesBMW i Series Engines Fuel Type
BMW i Series Engines by Fuel Type
Choose your BMW i Series engine by fuel type to compare realistic replacement prices, known issues, and compatible UK supply options - from the early i3 60Ah pure electric to the latest iX M60.
BMW i Series Petrol Engines
PetrolPetrol engines in the i Series appear exclusively as range extender units in the i3 and as the rear-mounted turbo three-cylinder in the i8 plug-in hybrid - no pure petrol i Series exists.
Common BMW i Series Petrol Engine Families
- •B38A15R - 647cc two-cylinder range extender generator (i3 REx 60Ah to 120Ah)
- •B38A15T0 - 1.5L turbo three-cylinder hybrid engine (i8 Coupe, 2014-2018)
- •B38A15T0-2 - updated 1.5L turbo with 374hp combined output (i8 Facelift, i8 Roadster)
Found In
- •i3 REx (2014-2022) - B38A15R family range extender only
- •i8 Coupe (2014-2018) - B38A15T0 plug-in hybrid
- •i8 Coupe Facelift (2018-2020) - B38A15T0-2 plug-in hybrid
Known For
- •Range extender carbon buildup requiring periodic cleaning every 30k-60k miles
- •i8 timing chain wear and HPFP failure shared with conventional B38 engines
- •Generator bearing failure causing rattling noise on i3 REx units
Typical Petrol Models
- •i3 REx 60Ah
- •i3 REx 94Ah
- •i3 REx 120Ah
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BMW i Series Petrol Engines
PetrolPetrol engines in the i Series appear exclusively as range extender units in the i3 and as the rear-mounted turbo three-cylinder in the i8 plug-in hybrid - no pure petrol i Series exists.
Common BMW i Series Petrol Engine Families
- •B38A15R - 647cc two-cylinder range extender generator (i3 REx 60Ah to 120Ah)
- •B38A15T0 - 1.5L turbo three-cylinder hybrid engine (i8 Coupe, 2014-2018)
- •B38A15T0-2 - updated 1.5L turbo with 374hp combined output (i8 Facelift, i8 Roadster)
Found In
- •i3 REx (2014-2022) - B38A15R family range extender only
- •i8 Coupe (2014-2018) - B38A15T0 plug-in hybrid
- •i8 Coupe Facelift (2018-2020) - B38A15T0-2 plug-in hybrid
Known For
- •Range extender carbon buildup requiring periodic cleaning every 30k-60k miles
- •i8 timing chain wear and HPFP failure shared with conventional B38 engines
- •Generator bearing failure causing rattling noise on i3 REx units
Typical Petrol Models
- •i3 REx 60Ah
- •i3 REx 94Ah
- •i3 REx 120Ah
BMW i Series Electric (BEV) Drive Units
DieselPure electric drive units power most i Series models - from the pioneering i3 to the i4 sedan and iX flagship - all using BMW's eDrive technology.
Common BMW i Series Electric Motor Families
- •EM100 - first-generation 170hp unit (i3 60Ah, 2013-2016)
- •EM100-2 - revised 94Ah unit with upgraded bearings (i3 94Ah, 2016-2018)
- •EM200 - final 120Ah unit with reinforced rotor (i3 120Ah, 2018-2022)
Found In
- •i3 60Ah / 94Ah / 120Ah (2013-2022) - EM100 / EM100-2 / EM200
- •i4 eDrive40 / M50 (2021-2025) - EM200-2 / EM200-3
- •iX xDrive40 / xDrive50 / M60 (2021-2025) - EM300 / EM300-2
Known For
- •Rotor bearing wear causing whining noise (SI B61 02 17 covers EM100 series)
- •Inverter failure leading to sudden power loss
- •Thermal management faults on EM200 and EM300 series
Typical Electric Models
- •i3 60Ah / 94Ah / 120Ah
- •i4 eDrive40 / M50
- •iX xDrive40 / xDrive50 / M60
BMW i Series Plug-in Hybrid (PHEV) Engines
PHEVThe i8 pairs BMW's B38 turbo petrol engine with an eDrive electric motor, delivering supercar performance with EV-only urban capability.
Common BMW i Series Plug-in Hybrid Engine Codes
- •B38A15T0 - 1.5L turbo three-cylinder + 96kW front motor (i8 Coupe, 362hp combined)
- •B38A15T0-2 - updated calibration with 374hp combined (i8 Facelift, i8 Roadster)
- •Petrol engine drives rear wheels via six-speed automatic transmission
Found In
- •i8 Coupe (2014-2018) - B38A15T0
- •i8 Coupe Facelift (2018-2020) - B38A15T0-2
- •i8 Roadster (2018-2020) - B38A15T0-2
Important Notes
- •No pure petrol-only operation - electric motor always assists or runs independently
- •Hybrid system requires specialist diagnostics during engine replacement
- •Battery health inspection recommended when replacing B38 engine
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Not sure which fuel type your BMW i Series has- Enter your registration number above to instantly identify your engine code, fuel system and compatible replacement options - all backed by a minimum 12-month unlimited mileage warranty from UK BMW i Series specialists.
Engine YearsGet quotes for 2013-2016 BMW i3 60Ah replacement drive units →
BMW i Series Engines by YearWhat Was Fitted & WhenBMW i Series Engines by Year - What Was Fitted & When
This section covers all major powertrain changes across the BMW i Series production timeline from 2013 to the present, organised so owners can quickly identify their engine code and compare rebuilt drive unit or range extender prices from UK specialists.
⚙Key Changes
- ✓i3 60Ah pure electric launched (2013)
- ✓First mass-production carbon-fibre reinforced plastic (CFRP) passenger cell
- ✓Rear-axle mounted EM100 electric motor
- ✓BMW eDrive technology debut
▣Main Engines
EM100- 60Ah electric drive unit (170hp)
▰Popular Models
- •BMW i3 60Ah
- •BMW i3 60Ah Mega World
- •BMW i3 60Ah Giga World
- •BMW i3 60Ah Tera World
🔧Known For
- ✓Pioneering electric city car with distinctive design
- ✓Lightweight CFRP construction improves efficiency
- ✓Early bearing wear issues documented in SI B61 02 17
- ✓Rear-hinged "coach doors" for easy access
Engine Codes Covered:
EM100Not sure which year your BMW i Series was built- Enter your registration number and we'll identify the exact engine, model year, and compatible replacement options instantly - all backed by a minimum 12-month warranty from UK BMW i Series specialists.
FAQ