BMW 8 Series 840d Engine ReplacementCompare Prices & Get Quotes

A BMW 8 Series 840d engine replacement typically costs between £2,800 and £10,500 for the engine unit alone, depending on condition type. Used B57D30 units start from around £2,800, reconditioned from £5,000, and rebuilt from £7,000. Main dealer fitted prices can reach £14,000-£18,000, while independent specialist supply & fit is significantly more competitive.

• Used engine: £2,800-£5,000 (supply only)
• Reconditioned: £5,000-£8,000 (supply only)
• Rebuilt: £7,000-£10,500 (supply only, 12-month warranty)
• Fitted price: add £780-£1,040 labour for independent specialist
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Common warning signs that your BMW 840d's B57 engine may be failing include: persistent check engine light (often EGR or DPF-related), loss of power or sluggish acceleration, rough idling, metallic rattling from the engine on cold start (timing chain), AdBlue countdown warnings that don't clear after refilling, and excessive exhaust smoke or failed MOT emissions.

• EGR issues: rough idle, reduced power, increased emissions
• DPF problems: "exhaust filter full" iDrive message, forced regeneration active
• Timing chain wear: rattling noise on startup, engine misfires
• AdBlue faults: countdown warnings, NOx sensor codes
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Yes - a BMW 8 Series 840d with a failed engine is almost always worth replacing rather than scrapping. With used 840d values ranging from £27,500 to £55,000, a rebuilt engine at £7,000-£10,500 represents only 15-35% of the car's value. For a £40,000-£50,000 car that would otherwise be written off, engine replacement is financially the right decision.

• 840d vehicle value: typically £27,500-£55,000
• Rebuilt engine cost: £7,000-£10,500 (supply only)
• Replacement cost as % of value: 15-35% - well within viable range
• 12-month warranty on every rebuilt engine provides peace of mind
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The BMW 840d uses the B57 3.0-litre straight-six diesel with twin turbochargers, producing 320-340 hp and 680-700 Nm of torque. The 840i uses the B58 3.0-litre straight-six petrol engine, producing around 335 hp. The 840d delivers substantially more low-end torque (700 Nm vs ~500 Nm in the 840i) and significantly better fuel economy, making it the preferred choice for high-mileage UK drivers.

• 840d: diesel, 320-340 hp, 680-700 Nm, 0-60 in 4.9 secs
• 840i: petrol, ~335 hp, ~500 Nm, 0-60 in ~4.8 secs
• 840d fuel economy: 39.8 mpg combined
• Both use 8-speed Steptronic automatic and xDrive all-wheel drive
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A BMW 8 Series 840d engine replacement typically takes 2-3 days for a specialist workshop to complete. The B57 engine is a straight-six mounted longitudinally with xDrive all-wheel drive, so the job requires careful drivetrain disassembly. Allow 12-16 hours of labour at independent specialist rates (£780-£1,040 at £65/hour), plus additional time for diagnostics and road testing.

• Labour time: 12-16 hours
• Specialist labour cost: £780-£1,040
• Typical turnaround: 2-3 working days
• Supply & fit available through our UK specialist network
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Every rebuilt BMW 8 Series 840d engine supplied through EnginesMarket carries a minimum 12-month unlimited-mileage warranty. This covers manufacturing defects, component failure, and workmanship issues. Reconditioned engines typically come with 6-12 month warranties, while used engines usually have 3-6 month warranties or none at all. Always confirm exact terms with your chosen supplier before ordering.

• Rebuilt: 12-month unlimited-mileage warranty (minimum)
• Reconditioned: 6-12 month warranty typical
• Used: 3-6 month warranty or as-sold (check with supplier)
• Warranty covers defects, not damage from external causes