BMW 5 Series 520d Engine ReplacementCompare Prices & Get Quotes

A BMW 5 Series 520d engine replacement typically costs £1,600-£3,600 supply-only for rebuilt units, or £2,800-£5,500 fitted by a specialist. Prices vary by engine code and generation.

• Used N47D20 engines: £1,100-£1,600 supply-only
• Used B47D20 engines: £1,400-£2,000 supply-only
• Reconditioned N47D20 units: £1,800-£2,600 supply-only
• Rebuilt B47D20 units: £2,600-£3,600 supply-only
• Professional fitting adds £800-£1,500 depending on workshop location

Yes, the N47D20 engine in the E60 and F10 520d suffers from well-documented rear timing chain tensioner failures between 55,000-85,000 miles. However, proactive replacement or upgraded rebuilt units resolve the issue permanently.

• N47D20 fitted to 520d 2007-2014 carries highest UK replacement search volume
• Rear-mounted chain design complicates access; engine-out work increases labour costs
• Cold-start rattling is the primary warning symptom before catastrophic failure
• B47 successor (2014+) relocated timing chain to the front, dramatically improving reliability

A B47D20 engine can replace an N47D20 in most F10 520d models, but requires ECU remapping, wiring harness adaptation, and specialist verification.

• B47D20 shares mounting points with N47D20 in F10 chassis
• ECU software update essential for compatibility with newer engine management
• The upgrade resolves timing chain concerns and improves emissions compliance
• Professional installation is strongly recommended - not a DIY job

The classic symptoms are coolant loss without visible external leaks, white smoke from the exhaust, and a sweet smell from the exhaust pipe. The engine may run rough or trigger a warning light.

• Coolant level drops without visible leaks is the earliest warning sign
• White smoke from exhaust (steam from coolant burning)
• BMW issued recalls for EGR cooler defects on many B47-powered models
• Ignoring EGR cooler failure can lead to hydrolock and full engine replacement

With proper maintenance, BMW 5 Series 520d diesel engines commonly reach 150,000-200,000 miles before major work. N47 engines may require timing chain replacement around 80,000 miles, while B47 engines typically last longer with fewer major issues.

• Regular oil changes with BMW LL-04 spec fluid are critical for N47 longevity
• DPF regeneration cycles require regular motorway driving
• B47 engines benefit from front-mounted chain design and improved thermal management
• Rebuilt engines with upgraded components can match or exceed original lifespan

For an E60 520d worth £2,500-£5,000, a rebuilt N47 at £2,200-£3,400 can make sense if the body, gearbox, and interior are in good condition. For F10 and G30 examples, replacement is generally viable given higher retained values.

• Compare replacement cost against vehicle value - replacement is viable up to 70% of car's value
• F10 520d values have stabilised; a good example justifies investment
• B47 engines in G30 command higher value - replacement more easily justified
• Always factor 12-month warranty into replacement decision