The more powerful diesel in BMW's first compact hatchback, the 120d E87 pairs 177 hp (later 163 hp) with rear-wheel drive for a genuinely sporty small car. The N47 engine replaced the older M47 in March 2007, bringing common-rail injection and more power but also the well-documented rear-mounted timing chain weakness. With proper oil changes and attentive maintenance, many N47 120d models reach high mileages, but the timing chain issue remains the defining risk factor.
Engaging rear-wheel-drive dynamics
Strong performance for its class
N47 timing chain at rear of engine
EGR cooler fire risk recall
Buy if: You want a sporty diesel hatchback with rear-wheel drive and can find one with documented short oil change intervals and no cold-start rattle.
Avoid if: The car has cold-start chain rattle, unknown service history, or was primarily driven on short urban trips.
Expected Annual Maintenance Costs
Common Problems
Rear-mounted timing chain stretches, causing cold-start rattle and risking catastrophic engine damage · more· less
The N47 engine positions its timing chain at the rear, between engine and gearbox. The chain, guides, and tensioner are prone to premature wear. BMW fitted an excessively sharp-edged crankshaft sprocket from the factory, causing accelerated chain wear. Cars produced between March 2007 and January 2009 are most severely affected, though the issue persists across the N47 range. BMW revised components in 2009 and again in 2011, significantly improving but not eliminating the problem. Symptoms begin with a metallic rattle on cold start lasting 1-30 seconds. Once audible, the chain has already stretched significantly. Replacement requires gearbox removal and costs approximately €1,500-2,750 at an independent specialist in Western Europe. If the chain snaps, it causes catastrophic valve-piston contact requiring engine replacement at €3,500-7,000. Prevention: change oil every 10,000 km (not BMW's recommended 25,000 km long-life interval) using quality 5W-30. The 120d's higher output (177 hp) compared to the 118d (143 hp) puts slightly more stress on these components.
EGR cooler can leak coolant which combines with soot at high temperatures, creating a fire risk · more· less
BMW issued a major recall affecting approximately 800,000 diesel vehicles worldwide due to defective EGR coolers. Coolant can escape from the cooler and combine with diesel soot accumulation at high temperatures, potentially causing the intake manifold to melt and, in rare cases, vehicle fires. The recall affects all N47-powered models including the 120d E87. BMW has acknowledged that prior corrective actions were inadequate, and an optimized cooler unit from a different supplier has only been used since 2022. The recall repair is free at BMW dealers, but many cars may still not have had it completed. If the recall has been done, cost is zero. If the car needs repair outside the recall (unlikely but possible), EGR cooler and valve replacement costs €600-1,500 at an independent workshop. This is a safety-critical item that must be verified before purchase.
Plastic swirl flaps in the intake manifold become brittle and can break into the engine · more· less
The N47 intake manifold contains plastic swirl flaps that control airflow to optimize combustion. Over time, engine heat and vibration cause the plastic to become brittle. The flaps or their mounting clips can break loose and be ingested into the combustion chamber, causing piston damage, valve damage, and potentially destroying the turbo on the way out. If caught early, preventive blanking with aluminium plates costs just €20-40 for parts plus approximately one hour of labor (€100-150 total). If swirl flap fragments enter the engine, repair costs escalate dramatically: cylinder head repair at a specialist costs approximately €2,000-3,000, while a new engine from BMW runs €8,500-13,500 fitted. Preventive blanking is strongly recommended on any N47 that has not already had this done. By 150,000 km, the risk becomes significant.
Diesel particulate filter blocks on cars driven primarily in urban traffic · more· less
The N47-powered 120d has a DPF that requires sustained highway driving above 60 km/h to regenerate. Cars used mostly for short urban trips accumulate soot faster than the filter can burn it off. Failed regenerations lead to a blocked DPF, causing power loss, increased fuel consumption, and warning lights. Professional DPF cleaning costs €200-350. If the filter is ash-saturated, back-flushing runs €400-600 or full replacement costs €1,000-1,800. Using a diagnostic tool to check soot loading before purchase is highly recommended. Cars with regular motorway use rarely experience this problem.
Electronic wastegate actuator sticks from carbon buildup, causing limp mode and power loss · more· less
The N47 turbocharger uses an electronically controlled wastegate. The actuator mechanism can stick from carbon buildup, particularly on gently driven cars or those used only for short trips. The actuator spring is also prone to premature failure due to insufficient lubrication. Symptoms include EPC warning light, limp mode, significant power loss, and up to 50% increased fuel consumption. BMW does not sell the actuator separately, so their quote includes full turbo replacement at €1,500-2,500. Specialist repair services can rebuild the actuator for €400-600. Regular spirited driving and highway use helps prevent carbon buildup on the vanes. The 120d's higher output means the turbo works harder than in the 118d, though failure rates are similar.
DMF springs weaken, causing judder on take-off and rattling at idle · more· less
Manual-equipped 120d models develop clutch judder when moving off, especially on inclines and when cold. The dual mass flywheel wears and develops excessive play, producing vibration through the pedal and drivetrain. The 120d's 350 Nm of torque (compared to the 118d's 300 Nm) puts more stress on the DMF and clutch assembly. Combined replacement costs €800-1,500 at an independent specialist, with parts (flywheel €250-400, clutch kit €150-250) plus approximately 6.5 hours of labor. This typically becomes necessary between 80,000-130,000 km depending on driving style. Urban stop-start driving accelerates wear significantly.
Rear subframe corrodes on exposed edges, potentially compromising structural integrity · more· less
The E87 rear subframe is prone to corrosion on its lower edges where it catches stone chips, salt, and wheel spray. The problem is accelerated in coastal areas and regions that use road salt. Several E87 owners have reported subframes corroding so severely they snapped, damaging brake lines. Finding a rust-free replacement subframe is difficult, as most used ones are already corroded. Preventive treatment involves wire brushing surface rust and applying wax-based rust inhibitor every two years (€50-100). Professional sandblasting and POR-15 coating costs €300-500. Sourcing and fitting a replacement subframe costs €800-1,500 including labor. Powder coating a new subframe before installation is the best long-term solution.
Water enters boot through rear vents and light seals, soaking the PDC module and causing electrical faults · more· less
The E87 boot area is prone to water ingress through rectangular vent panels behind the trim and through poorly sealed rear light housings. Water accumulates and soaks the PDC (parking distance control) module housed in the right-hand side of the boot. A waterlogged PDC module sends corrupted signals on the CAN bus, causing cascading electrical faults including instrument cluster failure, loss of speedometer and rev counter, and random warning lights. DIY fix involves resealing the vents and light housings (€10-20 in sealant). Drilling a small drain hole in the bung below the PDC module prevents reoccurrence. If the PDC module is corroded beyond repair, replacement costs €150-300. If other modules are affected by CAN bus interference, diagnosis and repair can reach €500.
N47 timing chain is a serious concern requiring vigilant maintenance
The BMW 120d E87 with the N47 engine can deliver reliable service if maintained with short oil change intervals (10,000 km maximum) and the known weak points are addressed proactively. The timing chain is the defining risk: early-production cars (2007-2009) are most vulnerable, but all N47 models require attention. Preventive swirl flap blanking is inexpensive insurance against catastrophic engine damage. The EGR cooler recall must be verified as completed. Beyond these engine-specific concerns, the E87 shares typical aging issues like rear subframe corrosion and boot water ingress. Cars with documented maintenance, no cold-start rattle, and completed recall work can still provide enjoyable, fuel-efficient motoring.
Recalls and Technical Service Bulletins
EGR cooler leak / fire risk (N47 diesel models, 2007-2011)
Critical - verify completed
Takata airbag inflator replacement (various production periods)
Verify completed
Fuel filter heater wiring (certain diesel models)
Verify completed
The EGR cooler recall is the most critical item. BMW recalled approximately 800,000 diesel vehicles worldwide for this fire safety issue, and has acknowledged that earlier repair attempts were insufficient. Contact BMW with the VIN to verify all recalls have been completed. Do not purchase an N47-powered car without confirming the EGR cooler recall status.
Warranty Status
Factory warranty (2 years)
Expired on all E87 models
Rust perforation warranty (12 years)
Expired on all E87 models
All BMW 120d E87 models are well outside their original 2-year factory warranty and 12-year rust perforation warranty. No factory extended warranty programs remain available from BMW for this generation. Third-party warranty providers may offer coverage but typically exclude known problem areas like timing chains and turbochargers on N47 engines.
This report is for informational purposes only and does not constitute professional advice. Estimates may be inaccurate. Always have a qualified specialist inspect the vehicle before purchase. We accept no liability for decisions made based on this information.