The E90 320d is one of BMW's most popular diesel saloons, known for good fuel economy (50+ mpg) and decent performance. Two different engines were used: the M47 (2005-2007, 163 hp) with timing chain at the front is considered reliable, while the N47 (2007-2011, 177 hp) has the infamous rear-mounted timing chain prone to catastrophic failure - especially on 2007-2009 cars. Listen for cold start rattle, verify oil change history, and check if EGR cooler recall has been completed. DPF issues are common on short-journey cars. With proper maintenance, high-mileage examples (200,000+ km) are achievable.
Rear-mounted chain stretches and can snap, destroying the engine · more· less
The N47 engine (2007-2011) has the timing chain at the rear of the engine, making replacement extremely labor-intensive. The chain tensioner can fail, causing the chain to stretch and eventually skip or snap. If caught early (rattling on cold start for 1-30 seconds), preventive replacement costs €1,500-2,500. If the chain snaps, valves hit pistons and the engine is destroyed - replacement engine with fitting costs €6,000-8,000. Cars built March 2007 to January 2009 are highest risk. BMW issued a "quality enhancement" recall but did not proactively contact owners. Post-2011 cars have improved tensioners with significantly lower failure rates. The M47 engine (2005-2007) has the chain at the front and does not have this issue.
Inlet manifold butterfly flaps can break off and be ingested by the engine · more· less
The M47 engine uses swirl flaps in the inlet manifold to vary intake tract length. These flaps can fatigue and break off, being sucked into the engine and causing catastrophic damage to pistons and valves. Preventive fix: blanking plate kit costs only €40-50 and eliminates the risk entirely. Most owners near 100,000 km get them removed or blanked. If the flaps have already been ingested, a full engine rebuild costs €3,500-4,000+. This issue primarily affects the M47 engine (2005-2007), not the N47.
Turbocharger failure€1,200 - €3,000
Oil starvation or actuator failure causes power loss and limp mode · more· less
The E90 320d uses a Mitsubishi turbocharger. Contaminated or degraded engine oil is responsible for 60% of turbo failures - the bearings starve and fail. Symptoms include white/black smoke, whistling, power loss, and limp mode. The turbo actuator can also fail separately, causing intermittent power loss. Actuator-only repair costs €500-700 at a specialist. Full turbo replacement costs €1,200-2,500 at independent shops, or €2,500-3,000+ at BMW dealers. Prevention: use quality oil and change every 10,000 km maximum rather than BMW's longer intervals.
DPF regeneration problems€200 - €1,500
Filter clogs on short journeys, fails to regenerate causing limp mode · more· less
The diesel particulate filter (DPF) needs to regenerate by burning off soot at high temperatures. This requires driving at 60+ mph for 15-25 minutes with coolant above 75°C and 10+ liters of fuel. Short urban journeys prevent regeneration, causing the DPF to clog. Thermostat failure (common on E90s) can prevent the engine reaching proper temperature. Diagnostic clearing and forced regeneration costs €100-200. Professional DPF cleaning costs €400-700. Full DPF replacement costs €800-1,500. A DPF can last 250,000+ km with regular motorway driving, or fail at 60,000 km with only city use.
EGR cooler leak (fire risk)€0 (recall)
Internal coolant leak can cause smoldering and engine fires · more· less
BMW issued recalls (18V-755 in 2018 and 21V-907 in 2021) for EGR cooler failures on N47 diesel engines. The cooler can develop an internal coolant leak; coolant mixes with soot and high temperatures can cause flammable deposits, potentially leading to engine fires. Nearly 800,000 vehicles were affected worldwide. Warning signs: coolant loss warning, exhaust gas smell, reduced power. The repair is free under recall - dealerships replace the EGR cooler and inspect the intake manifold. Verify recall completion with BMW using your VIN.
Dual mass flywheel / clutch wear€900 - €1,500
Juddering clutch typically requires expensive flywheel replacement · more· less
Manual transmission E90 320ds use a dual mass flywheel (DMF) to smooth power delivery. The DMF cannot be machined and must be replaced when worn. Symptoms: juddering when pulling away, rattling at idle with clutch depressed. Clutch and DMF replacement together costs €900-1,200 at independent specialists, or €1,500+ at BMW dealers. Parts alone (LuK clutch kit with DMF) cost €400-600. Typically needed between 130,000-200,000 km depending on driving style. City driving and stop-start traffic accelerates wear.
Glow plug / controller failure€150 - €400
Hard cold starts and DPF regeneration problems · more· less
Glow plugs typically wear out around 150,000-160,000 km. Symptoms: rattlier/noisier cold starts, harder starting in cold weather, DPF warning lights (faulty glow plugs prevent DPF regeneration). The glow plug controller is located under the intake manifold and often fails alongside the plugs - replace both together. Glow plugs cost €15-20 each (4 required). Controller costs €80-150. Labor is €100-200 due to poor accessibility. Total job: €300-450 including parts and labor.
Thermostat / water pump failure€400 - €900
Engine runs cold or overheats, prevents DPF regeneration · more· less
E90 thermostats are known to fail, causing the engine to run too cold (stuck open) or too hot (stuck closed). A cold-running engine prevents DPF regeneration and reduces cabin heating. The diesel 320d uses a mechanical water pump (not electric like the petrol versions). Parts cost €150-300 for thermostat housing and water pump. Labor adds €250-400. Many owners replace both together preventively as they share coolant and the job overlaps. Total: €400-700 at independents, €700-900 at dealers.
Oil filter housing gasket leak€300 - €700
Common oil leak requiring gasket replacement · more· less
The oil filter housing gasket is a known failure point on E90s. The gasket hardens and becomes brittle over time, causing oil leaks. Oil can drip onto the exhaust or mix with coolant if the leak is severe. Parts cost only €30-50 for the gasket kit. Labor is €250-500 depending on shop and what else is done at the same time. Many owners combine this with thermostat/water pump replacement as the jobs overlap. Total: €300-500 at independents, €500-700 at dealers.
Injector failure€400 - €1,500
Diesel injectors can fail causing rough running and smoke · more· less
Diesel injectors can fail due to contaminated fuel or general wear. Symptoms: rough idle, black smoke, poor fuel economy, misfires. BMW recommends replacing all 4 injectors together when one fails ("blanket repair"). Individual injector replacement costs €150-300 per injector including labor. Full set replacement costs €800-1,500 at independent shops. Remanufactured Bosch injectors are available and come with warranty. Less common than other issues but can occur on high-mileage cars or those run on poor quality diesel.
Window regulator failure€100 - €250
Electric window mechanism breaks, window stuck or falls into door · more· less
Failed window regulators were common on E90s. Symptoms: clicking/grinding noise, window moves unevenly, stops midway, or falls down into the door. Parts cost €50-125 for aftermarket regulators, €100-200 for genuine BMW. Labor is €50-100 per door. The motor can often be reused - only the mechanical regulator needs replacement. A relatively minor repair but annoying if the window gets stuck open.
Engine choice matters significantly
The E90 320d's reliability depends heavily on which engine it has. The earlier M47 (2005-2007) is considered robust with swirl flaps being the main concern - easily prevented with cheap blanking plates. The N47 (2007-2011) is more powerful but the timing chain issue is serious, especially on 2007-2009 cars. If buying an N47, verify the timing chain has been replaced or listen carefully for cold start rattle. Regular oil changes (10,000 km max) and avoiding only short trips will dramatically improve longevity.
Pre-Purchase Inspection Checklist
General checks
Service history
Complete service records essential. Verify oil changes at 10,000-15,000 km intervals - BMW's 30,000 km interval is too long for these engines.
Tires
Check tread depth, age, and uneven wear patterns. Common size is 205/55 R16 or 225/50 R17.
Cold start
Must start engine completely cold. Listen for unusual sounds in the first 30 seconds.
Body condition
Check for rust, accident damage, paint mismatch. Wheel arch corrosion can occur.
Test drive
Minimum 30 minutes including motorway driving to allow full operating temperature and DPF regeneration.
Specific for this vehicle
Cold start timing chain rattle (N47 only)
On 2007-2011 cars, listen for rattling in the first 1-30 seconds of cold start from the back of the engine. Any rattle means chain replacement is needed. This is the most critical check.
Identify which engine (M47 vs N47)
Check exhaust: downturned tip = M47 (2005-2007), straight tip = N47 (2007-2011). Also, start/stop feature indicates N47. M47 has no timing chain concerns.
DPF condition and driving history
Ask about typical journeys. Short city trips clog the DPF. Check for DPF warning lights. Request a diagnostic scan to check DPF soot and ash levels.
Verify EGR cooler recall completed
For 2007-2011 N47 cars, confirm recalls 18V-755 and 21V-907 have been performed. Contact BMW with VIN to verify.
Check for oil leaks
Inspect around oil filter housing, valve cover, and turbo oil lines. Oil leaks are common and indicate pending maintenance.
Turbo operation
During test drive, accelerate firmly and feel for smooth power delivery. Hesitation, whistling, or sudden power loss indicates turbo issues.
Swirl flap status (M47 only)
On 2005-2007 cars, ask if swirl flaps have been blanked off. If unknown and over 100,000 km, consider this a priority maintenance item.
Coolant temperature behavior
After driving, check that temperature gauge reaches and maintains 90°C. If it stays below 80°C or fluctuates, the thermostat may be failing.
Recalls and Technical Service Bulletins
EGR cooler fire risk (N47, 2007-2011)Verify completed
Blower motor wiring (various years)Verify completed
N47 timing chain "quality enhancement"Not a formal recall
Contact BMW with the VIN to verify all recalls have been completed. The EGR cooler recall is particularly important for N47 diesel engines due to fire risk. Note that the timing chain issue was addressed via a "quality enhancement" program, not a formal recall - BMW did not proactively contact owners, so many cars may never have had the updated parts fitted.
Warranty Status
Factory warranty (2 years)Expired on all E90s
Extended warrantyThird-party only
All E90 320d models (2005-2011) are now well outside their original factory warranty. Third-party extended warranties are available but typically exclude pre-existing conditions and high-wear items. Given the age of these vehicles, a pre-purchase inspection and setting aside a repair fund is more practical than warranty coverage.
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.