BMW 4 Series N47/B47/B58/N57 Engine SolutionsUK Specialists

A rebuilt BMW 4 Series engine typically costs £1,226 to £4,800 supply-only, depending on engine code, variant and condition. Diesel N47/B47 units sit at the lower end, while performance B58 or S55 engines command premium pricing. Supply and fit installation adds £650-£1,150 labour depending on workshop location and xDrive complexity.

• N47D20C rebuilt engines start around £1,226 for 420d variants
• B47D20A modern diesel replacements range £1,400 to £2,800 supply-only
• Performance S55B30A M4 engines cost £5,200 to £8,800 rebuilt
• All prices exclude fitting labour and vary by supplier warranty terms
• Reconditioned units offer mid-tier pricing between used and remanufactured options

Early BMW 4 Series N47D20C diesel and N20B20B petrol engines (2013-2016) are most affected by timing chain wear, with failures commonly occurring between 60,000-90,000 miles. The later B47 and B48 engines relocated the chain to the front, significantly improving long-term reliability and reducing urgent replacement enquiries across the model range.

• N47D20C rear-mounted chain design causes tensioner and guide wear
• Cold-start rattling is the primary warning symptom before catastrophic failure
• B47D20A front-chain update from 2015 onwards resolves most timing concerns
• N20B20B petrol units share similar plastic guide degradation risks
• Rebuilt engines include upgraded metal guides and revised tensioner kits

Yes, a B47D20A engine can replace an N47D20C in most BMW 4 Series 420d models, but requires ECU remapping, wiring harness adaptation and specialist verification. The upgrade resolves timing chain concerns and improves emissions compliance, though fitment complexity means professional installation is strongly recommended.

• B47D20A shares mounting points with N47D20C in F32/F33 chassis
• ECU software update essential for compatibility with newer engine management
• xDrive models need transfer case calibration after engine swap
• Upgrade typically costs £200-£400 more than like-for-like N47 replacement
• Verified compatibility checks prevent costly fitment errors during installation

Every BMW 4 Series engine supplied through EngineMarket includes a minimum 12-month unlimited mileage warranty as standard. Premium remanufactured units often carry 24-month coverage, while used engines typically offer 3-6 months. Always confirm exact terms, claim process and labour coverage with your chosen UK specialist supplier before ordering.

• Rebuilt and reconditioned engines include 12-month unlimited mileage warranty minimum
• Remanufactured units often feature extended 24-month coverage for peace of mind
• Used engine warranties vary by breaker, typically 3-6 months parts-only
• Labour coverage depends on supply-only versus supply-and-fit service selection
• Warranty claims require proof of professional installation and service history

A low-mileage used BMW 4 Series engine can be reliable if sourced from a verified breaker with compression test results and full service history documentation. However, unknown maintenance intervals, hidden internal wear and lack of upgraded timing components mean rebuilt units often provide better long-term value and comprehensive warranty protection for most private and fleet owners.

• Verify donor vehicle mileage via DVLA records before purchasing any used unit
• Request compression test results and oil pressure readings from the supplier
• Used engines lack upgraded timing components that address known N47 weaknesses
• Budget for potential ancillary replacement like turbos, injectors or cooling systems
• Minimum 3-month warranty recommended to cover early failure risks

Reconditioned BMW 4 Series engines receive targeted repairs to worn components like seals and gaskets, while remanufactured units undergo complete strip-down with new bearings, pistons and machining to factory tolerances. Remanufacturing costs more but delivers near-zero-hour reliability and longer warranty coverage for high-mileage or performance variants.

• Reconditioned units replace visibly worn parts; remanufactured engines rebuild all critical components
• Remanufacturing includes cylinder honing, crank polishing and pressure testing as standard
• Reconditioned pricing typically £1,450-£3,100; remanufactured £2,800-£4,800 supply-only
• Both options include upgraded timing components to resolve known N47 weaknesses
• Remanufactured engines often carry 24-month warranties versus 12-month for reconditioned

With full service history and timely oil changes, BMW 4 Series B47 diesel and B48 petrol engines regularly exceed 150,000 miles before major work. Earlier N47 and N20 units may require timing chain replacement around 80,000 miles, but rebuilt engines with upgraded components can match modern reliability expectations.

• B47D20A and B48B20A engines benefit from front-chain design and improved cooling
• Annual oil changes using BMW Longlife-04 spec prevent premature turbo wear
• DPF regeneration cycles require regular motorway driving to avoid clogging issues
• Rebuilt engines with upgraded guides and tensioners reset the reliability clock
• High-mileage fleet 420d models often reach 200,000 miles with specialist care

A Euro 6-compliant rebuilt BMW 4 Series engine will pass MOT emissions testing when installed correctly with updated ECU mapping. Ensure your supplier provides emissions documentation and that the replacement matches your vehicle's original Euro standard to avoid compliance issues during annual testing or ULEZ zone entry.

• Euro 6 B47D20A and B58B30A engines meet current MoT emissions limits
• DPF and AdBlue systems must be functional and correctly calibrated post-installation
• ECU remapping may be required to clear fault codes after engine swap
• Retain all emissions certification paperwork for MoT tester verification if requested
• Non-compliant engines risk MoT failure and potential ULEZ charge liabilities

Yes, EngineMarket's UK specialist network offers supply and fit packages for BMW 4 Series engine replacements nationwide. This turnkey service includes engine delivery, professional installation, fluid flushing and post-fit diagnostics, typically adding £650-£1,150 to the base engine price depending on variant complexity and workshop location.

• Supply and fit removes coordination risks between parts supplier and local garage
• xDrive and M4 variants require specialist calibration included in fitting package
• Most installations complete within 2-3 working days from engine dispatch
• Warranty coverage often extends to labour when using network-approved fitting centres
• Post-installation road test and fault code clearance included as standard

Check your BMW 4 Series VIN plate under the bonnet or driver's door jamb for the engine code, or enter your registration on the DVLA website for instant variant identification. Matching the exact code like N47D20C or B48B20B ensures compatibility and prevents costly fitment errors during replacement.

• VIN lookup reveals exact engine code, chassis generation and production date
• Engine codes are stamped on the block near the oil filter housing
• B47D20A replaced N47D20C in 420d models from late 2015 onwards
• xDrive variants require additional transfer case compatibility verification during ordering
• EngineMarket's registration tool instantly matches your variant to available rebuilt units