BMW 6 Series 635d Engine ReplacementCompare Prices & Get Quotes

A BMW 6 Series 635d engine replacement typically costs £1,800-£3,200 for a used M57D30 unit, £2,800-£4,800 for a reconditioned engine, and £4,000-£6,000 for a fully rebuilt engine with warranty. Supply & fit adds £780-£1,040 in specialist labour (12-16 hours).

• Used engines: lowest upfront cost, limited warranty
• Reconditioned: mid-range, some new parts fitted
• Rebuilt: highest cost, fully restored to factory spec with 12-month warranty

Common symptoms include metallic rattling noise from the front of the engine on cold start, rough idling, engine misfires, and loss of low-end responsiveness. In advanced cases, the engine may struggle to start or show a timing-related fault code. If you hear a rattle, have it inspected immediately - a snapped chain can destroy the cylinder head and valves.

• Rattling on start-up: first warning sign
• Rough idle / misfires: chain elongation affecting timing
• Loss of power: timing error reducing performance

With average values of £5,300-£6,500, a full rebuilt engine at £4,000-£6,000 represents a significant investment. However, if your 635d is in excellent condition with low mileage, a rebuilt engine can extend its life by 150,000+ miles - often cheaper than buying a replacement car of similar specification.

• Sub-£5,000 car: consider a used engine or timing chain repair
• £5,000-£7,000 car: reconditioned engine is viable
• £7,000+ car: rebuilt engine with warranty makes strong financial sense

A typical BMW 6 Series 635d engine replacement takes 2-4 days for supply and fit at a specialist garage. The M57D30 is a straight-six with good engine bay access, but the job requires dropping the subframe and removing the gearbox. Most specialists offer collection/delivery options nationwide.

• Same-day dispatch available for in-stock engines
• Fitting typically completed within 3 working days
• Collection/delivery options available across the UK

The 635d uses the 3.0L M57D30 twin-turbo diesel (286hp, 580Nm), while the 630i uses a 3.0L N52 or N53 naturally aspirated petrol (258-272hp). The 635d offers substantially more torque (580Nm vs ~320Nm), better fuel economy (40.9mpg combined), but higher engine replacement costs due to the complexity of the twin-turbo diesel system.

• 635d: twin-turbo diesel, 286hp, 580Nm torque
• 630i: naturally aspirated petrol, 258-272hp
• 635d replacement cost: £1,800-£6,000 vs 630i: lower

The M57D30 is considered one of BMW's most reliable diesel engines, with many examples exceeding 200,000-300,000 miles when properly maintained. The key to longevity is regular oil changes with BMW LL-04 approved oil, avoiding short urban trips (to prevent DPF clogging), and addressing timing chain rattles early.

• Regular oil changes: critical for chain and turbo health
• Motorway driving: helps DPF regenerate
• Early diagnosis: catch timing chain wear before failure