BMW 4 Series 418d Engine ReplacementCompare Prices & Get Quotes

A BMW 4 Series 418d engine replacement typically costs between £3,200 and £5,500 for a reconditioned unit, with rebuilt engines ranging from £3,800 to £5,800 for the B47D20A and £4,500 to £6,500 for the N47D20U1. Used engines start from around £1,800. These prices are supply-only - fitting adds 8-12 hours of labour at specialist rates (£520-£780).

• Reconditioned B47D20A: £2,800-£4,500
• Rebuilt B47D20A: £3,800-£5,800
• Rebuilt N47D20U1: £4,500-£6,500 (estimated)

The N47D20U1 engine fitted to early BMW 4 Series 418d models (2014-2015) is known for timing chain issues. The most common early warning is a metallic rattling noise on cold start that wasn't there before, or a rattle at idle that changes when you touch the accelerator.

• Don't ignore cold-start rattle - it's the chain tensioner failing
• If the chain snaps, valves collide with pistons - engine is destroyed
• B47D20A engines (2015-onwards) have a front-mounted chain and are far less prone to this issue

It depends on your car's value and condition. For a 2014-2017 BMW 4 Series 418d worth £4,000-£10,000, a rebuilt engine at £3,200-£5,500 is a significant investment but often worthwhile if the car is otherwise in good condition. For cars under £5,000, carefully evaluate whether a used engine or repair makes more financial sense.

• Cars worth £4,000-£8,000: consider a used or reconditioned engine
• Cars worth £8,000+: a rebuilt engine with warranty is usually the best long-term value
• Always factor in the car's overall condition - not just the engine

Both the 418d and 420d use 2.0-litre turbo-diesel engines, but the 420d is tuned for higher output. The 418d produces 143-150bhp, while the 420d produces approximately 181-190bhp. The engines share the same basic architecture - N47 in early cars, B47 in later models - but the 420d features a different turbocharger and engine calibration.

• 418d: entry-level diesel, 143-150bhp, best fuel economy
• 420d: higher-output diesel, ~181-190bhp, more performance
• Both use the same engine family - many components are interchangeable

A BMW 4 Series 418d engine replacement typically takes 2-3 days for a specialist workshop to complete, assuming the replacement engine is already in stock. This includes removal of the old engine, fitting the replacement, and full system testing.

• Supply only: 1-2 days for delivery
• Supply & fit: 2-3 days in the workshop
• Some specialists offer same-day dispatch on qualifying orders

Yes - a B47D20A engine from a 2015-onwards BMW 4 Series 418d is a direct physical fit for earlier N47D20U1 cars. The B47 offers significantly better reliability thanks to its front-mounted timing chain design. However, you'll need to ensure the engine management software is correctly calibrated for the newer engine.

• Direct physical fit: B47 mounts in the same way as N47
• ECU calibration: will need updating for the B47 engine
• Emissions compliance: ensure Euro 6 standards are met

Every rebuilt and reconditioned engine supplied through EnginesMarket carries a minimum 12-month unlimited-mileage warranty. Some suppliers offer extended warranties of up to 24 months on certain engine types. Always confirm exact terms with your chosen supplier before purchase.

• 12-month unlimited-mileage: minimum standard
• 24-month options: available on many premium rebuilds
• Warranty covers: manufacturing defects and component failure