4 Series Diesel Engines
from £1,200 to £4,200
Rebuilt units from £1,226 · Common codes: N47D20C, B47D20A, B47D20B
BMW ENGINE MARKETPLACE
BMW 4 Series N47/B47/B58/N57 Engine Solutions - UK Specialists
Get quotes from trusted UK BMW 4 Series engine specialists. Compare reconditioned & used engines for 418d to M4 - N47/B47/B58/N57 covered. Get a quote before it's too late.
Supply & Fit Available
12-Month Warranty
Nationwide Delivery
100+ Suppliers
4 Series Petrol Engines
from £1,300 to £3,900
Rebuilt units from £1,350 · Common codes: N20B20B, B48B20A, B48B20B
4 Series Performance Engines
from £3,500 to £9,500
Rebuilt units from £3,500 · Common codes: N55B30A, B58B30A, S55B30A
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Compare reconditioned, rebuilt & used engine prices
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 4 Series Replacement Engineto Finding the Best BMW 4 Series Replacement Engine
12-Month Warranty
Supply & Fit Available
Nationwide Delivery
Trusted UK Suppliers
Most replacements completed within 3-5 days.
Live UK Engine Market Data
What Are UK Drivers Paying for BMW 4 Series Engine Replacement
The table below shows typical UK rebuilt engine costs across BMW 4 Series variants, covering documented failure causes, engine codes, fuel types and displacement 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 4 Series engines through EngineMarket.
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Variants We Cover
BMW 4 Series Engine ReplacementAll Variants Covered
4 Series M4
S55B30A/S58B30A 3.0L Petrol
Rebuilt Engines: £5,500-£11,500
Not sure which variant your BMW 4 Series is- Enter your registration number above - we'll identify the exact sub-model, engine code and compatible replacement options instantly.
4 Series
Engine Codes
BMW 4 Series Engine CodesFull Technical Specifications & Replacement Guide
Every engine code fitted to the BMW 4 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.
Diesel Engines
Extracted from detailed diesel engine families across BMW 4 Series variants.
N47D20C - 2.0L Diesel
Main replacement triggers are timing chain wear, EGR / cooling faults and turbo-control issues.
Compatible variants
418d418d EfficientDynamics418d M Sport418d xDrive420d420d EfficientDynamics
Avg. rebuilt price
£1,226 - £2,400
Supply only
Technical specifications
- Fuel type
- Diesel
- Engine size
- 2.0L
- Power output
- 163-190 hp
- Years fitted
- 2013-2016
Common failures
- ●Main replacement triggers are timing chain wear, EGR / cooling faults and turbo-control issues.
- ●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 4 Series engine specialists. Every rebuilt engine comes with a minimum 12-month unlimited mileage warranty.
4 Series
Common Problems
BMW 4 Series Engine Problems - What It Costs to Fix & When Replacement Makes Sense
The BMW 4 Series delivers refined performance, but its early N47 diesel and N20 petrol engines are widely documented for premature timing chain wear, while modern B48 and B58 units frequently suffer cooling system degradation and plastic housing fatigue. Every rebuilt BMW 4 Series engine supplied through EngineMarket includes upgraded internal components...
BMW 4 Series Timing Chain Failure - Why N47 & N20 Engines Fail Prematurely
BMW 4 Series Timing Chain Failure
Most affected vehicles
BMW 4 Series 418d420d
BMW 4 Series 418d, 420d, 420i, 428i (2013-2016, N47D20C & N20B20B)
Failure mileage range
60,000 - 90,000 miles
Typical failure window
Root cause
The rear-mounted timing chain design on early N47 and N20 engines places extreme tension on thin plastic guides and a weak hydraulic tensioner, causing the chain to stretch, rattle, and eventually skip teeth under cold-start conditions.
Repair options & estimated costs (UK ranges)
| Repair tier | Dealer price | Specialist price | What it involves | Longevity / suitability |
|---|---|---|---|---|
| Minor - Preventative Chain Replacement | £1,800 - £2,500 | £1,100 - £1,600 | Engine-off chain swap, upgraded tensioner installation, reinforced plastic/metal guides, and timing recalibration | 80,000+ miles; only viable before valve-to-piston contact occurs |
| Intermediate - Cylinder Head Valve Repair | £3,200 - £4,500 | £2,000 - £3,000 | Timing chain replacement plus valve decarbonising, bent valve straightening, and head skimming after initial chain jump | Restores compression but leaves bottom-end chain tensioner weakness intact |
| Full Replacement - Rebuilt / Reconditioned Engine | £3,500 - £4,800 | £2,400 - £3,400 | Complete engine swap with a fully rebuilt unit featuring reinforced chain guides, updated tensioner, bench-tested performance and 12-month warranty | Permanent solution; upgraded internals eliminate the original factory weak point |
Our recommendation
If your BMW 4 Series is rattling on cold starts but still runs smoothly, a specialist preventative chain replacement with an updated tensioner kit offers excellent value and prevents catastrophic failure. Once the chain has skipped or you hear heavy mechanical knocking, the bottom end is likely compromised and a full rebuilt engine replacement becomes the only reliable, cost-effective option.
Compare rebuilt N47D20C & N20B20B BMW 4 Series engine quotes nowReplacement Engine Options
BMW 4 Series Engine TypesOptions, Costs & What to Expect
Every engine type is available through the uk network with typical price ranges based on variant, engine code and budget.
BMW 4 Series Reconditioned Engines (Recon)£1,450 - £3,100((supply only))
BMW 4 Series Rebuilt Engines£1,800 - £3,500((supply only))
BMW 4 Series Used Engines£750 - £1,650((supply only))
BMW 4 Series Remanufactured Engines£2,800 - £4,800((supply only))
BMW 4 Series Refurbished Engines£1,200 - £2,400((supply only))
Compare BMW 4 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 4 Series within hours.
Engine Sizes
BMW 4 Series Engines by SizeFind the Right Displacement for Your Variant
Every engine displacement fitted to the BMW 4 Series across all UK generations is listed below, complete with compatible factory codes, production years and known failure patterns for accurate replacement matching.
The 2.0L turbo diesel has been the commercial backbone of the 4 Series lineup since its F32 generation launch, evolving from the rear-chain N47 to the front-chain B47 family. It powers the high-volume 418d, 420d and 425d trims, offering a balance of torque, efficiency and fleet suitability with EfficiencyDynamics calibration. While the newer B47 resolves earlier timing concerns, both variants require strict oil service intervals to maintain turbo and DPF longevity.
⚙
Engine Code(s)
N47D20C, B47D20A, B47D20B, B47C20U0
▣
Compatible Models (UK)
418d, 418d EfficientDynamics, 420d, 420d xDrive, 425d
ϟ
Power output
Verified by registration
△
Common Failure Points
Timing chain tensioner wear, guide degradation on early N47 units, EGR cooler clogging on later B47 variants
Production Years: F32/F33/F36 2013-2020, G22/G23/G26 2020-present
Get quotes for BMW 4 Series 2.0L diesel enginesBMW 4 Series Engines Fuel Type
BMW 4 Series Engines by Fuel Type
Choose your BMW 4 Series engine by fuel type to compare realistic replacement prices, known issues, and compatible UK supply options - from early N47 diesel units to the latest B58 mild-hybrid petrol systems.
BMW 4 Series Diesel Engines
DieselDominating the UK replacement market, 4 Series diesel engines span F-generation fleet workhorses to modern G-generation Euro 6 specialists.
Common BMW 4 Series Diesel Engine Families
- •N47D20 - High-volume 420d replacement unit, notorious rear timing chain wear.
- •B47D20 - Modern 420d front-chain update resolving earlier timing vulnerabilities.
- •B47D20B - High-torque 425d twin-charged unit delivering enhanced mid-range pull.
Found In
- •F32/F33/F36 Coupe/Convertible/Gran Coupe (2013-2020) - N47, N57
- •G22/G23/G26 Coupe/Convertible/Gran Coupe (2020-present) - B47, B57
Known For
- •Exceptional motorway fuel economy and strong towing torque capacity.
- •N47 timing chain failures between 60k-90k miles driving urgent replacements.
- •DPF and EGR clogging on vehicles restricted to urban short-journey driving.
Typical Diesel Models
- •418d / 418d M Sport
- •420d / 420d xDrive
- •425d / 425d M Sport
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BMW 4 Series Diesel Engines
DieselDominating the UK replacement market, 4 Series diesel engines span F-generation fleet workhorses to modern G-generation Euro 6 specialists.
Common BMW 4 Series Diesel Engine Families
- •N47D20 - High-volume 420d replacement unit, notorious rear timing chain wear.
- •B47D20 - Modern 420d front-chain update resolving earlier timing vulnerabilities.
- •B47D20B - High-torque 425d twin-charged unit delivering enhanced mid-range pull.
Found In
- •F32/F33/F36 Coupe/Convertible/Gran Coupe (2013-2020) - N47, N57
- •G22/G23/G26 Coupe/Convertible/Gran Coupe (2020-present) - B47, B57
Known For
- •Exceptional motorway fuel economy and strong towing torque capacity.
- •N47 timing chain failures between 60k-90k miles driving urgent replacements.
- •DPF and EGR clogging on vehicles restricted to urban short-journey driving.
Typical Diesel Models
- •418d / 418d M Sport
- •420d / 420d xDrive
- •425d / 425d M Sport
BMW 4 Series Petrol Engines
PetrolSpanning efficient four-cylinder turbo units to acclaimed inline-six performance blocks, 4 Series petrol engines balance daily usability with sporting character.
Common BMW 4 Series Petrol Engine Families
- •B38B15 - Compact 418i three-cylinder turbo delivering efficient urban performance.
- •N20B20 - Early 420i/428i turbo four requiring upgraded timing tensioners.
- •B48B20 - 420i/430i closed-deck successor offering improved cooling reliability.
Found In
- •F32/F33/F36 Coupe/Convertible/Gran Coupe (2013-2020) - B38, N20, N55, S55
- •G22/G23/G26 Coupe/Convertible/Gran Coupe (2020-present) - B48, B58, S58
Known For
- •Direct injection efficiency paired with responsive Valvetronic turbocharging.
- •N20 timing chain guide degradation causing expensive early-life mechanical failures.
- •B48 plastic coolant pipe and thermostat housing leaks at higher mileages.
Typical Petrol Models
- •418i / 418i M Sport
- •420i / 420i xDrive
- •430i / 430i M Sport
BMW 4 Series Hybrid / Electrified Engines
MHEVUtilising a 48-volt belt starter generator to smooth stop-start operation and assist acceleration, MHEV systems enhance efficiency without compromising performance.
BMW 4 Series MHEV Engine Codes
- •B48B20A - Combustion module powering 430e with integrated electric rear axle.
- •High-voltage battery pack powers rear motor for short-range electric-only driving.
- •Petrol engine seamlessly engages once battery state-of-charge drops below threshold.
Found In
- •G22/G23/G26 430e / 430e xDrive (2021-present)
- •G22/G23/G26 M440i / M440i xDrive (2020-present)
Important Notes
- •Rebuilt combustion modules supplied separately from battery and inverter assemblies.
- •Specialist hybrid certification required for safe disconnect and recommissioning.
- •Availability of fully integrated replacement units is more limited than standard engines.
Not sure which fuel type your BMW 4 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 4 Series specialists.
Engine YearsCheck 2013-2014 BMW 4 Series engine replacement quotes →
BMW 4 Series Engines by YearWhat Was Fitted & WhenBMW 4 Series Engines by Year - What Was Fitted & When
Covering every major powertrain update from the 2013 launch to current G-generation models, this timeline helps you pinpoint your exact engine and compare rebuilt prices from UK specialists.
⚙Key Changes
- ✓F32 Coupe and F33 Convertible debut as standalone models
- ✓N47 diesel family replaces older units with rear-mounted timing chains
- ✓N20 and N55 turbo petrol engines introduced as primary performance options
- ✓xDrive all-wheel drive becomes available across diesel and petrol lineups
▣Main Engines
N47D20C- 2.0L diesel (418d / 420d)
N57D30A- 3.0L diesel (430d)
N20B20B- 2.0L petrol (420i / 428i)
N55B30A- 3.0L petrol (435i)
▰Popular Models
- •BMW 420d
- •BMW 428i
- •BMW 430d
- •BMW 435i
🔧Known For
- ✓High fleet penetration making 420d replacements a common workshop request
- ✓N47 rear timing chain tensioner weakness emerges around 60k-80k miles
- ✓N20 timing guide plastic degradation causes early catastrophic failures
- ✓Excellent chassis dynamics establish strong enthusiast following
Engine Codes Covered:
N47D20CN57D30AN20B20BN55B30ANot sure which year your BMW 4 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 4 Series specialists.
FAQ