The E90 320d is BMW's best-selling diesel sedan of its generation, offering rear-wheel-drive dynamics with good fuel economy. Two engines were fitted: the M47TU2 (163 hp) is a proven four-cylinder with manageable issues, while the N47 introduces the well-documented rear-mounted timing chain weakness. The 177 hp N47 went on sale in September 2007; from spring 2010 the standard 320d produced 184 hp and the EfficientDynamics Edition 163 hp. Identifying the engine is the most important step when buying.· more· less
Rear-mounted timing chain stretches and tensioner loses pressure, causing cold-start rattle and risk of catastrophic engine damage · more· less
The N47 engine (2007-2011 models) has the timing chain mounted at the rear of the engine, between the engine and gearbox. The chain tensioner bleeds oil pressure overnight, allowing the chain to slap on cold start. Cars built before BMW's 5 January 2009 crankshaft and chain-guide parts change are most severely affected. A further parts boundary followed on 1 March 2011, and chain-related work is still specified for N47T engines built after that date, so a later build date on its own does not rule the problem out. A distinctive rattling noise lasting 1-30 seconds on cold start is the earliest warning sign. If ignored, the chain can skip teeth and cause catastrophic valve-to-piston contact, destroying the engine. Replacement requires significant disassembly (engine removal on some configurations) and costs €1,500-2,500 at an independent specialist or €2,500-3,500 at a BMW dealer. Frequent oil changes (every 10,000 km maximum, using quality oil) are the best preventive measure. The earlier M47TU2 engine (2005-2007) uses a conventional front-mounted timing chain and is not affected by this issue.
Swirl flap failure
€150 - 4,0002 of 9
Intake manifold swirl flaps seize from carbon or break apart, risking engine damage if fragments enter cylinders · more· less
Both the M47TU2 and N47 engines have swirl flaps in the intake manifold. On the M47TU2 (163 hp), these are 22mm flaps that can work loose from vibration and carbon buildup. If a flap detaches and enters the combustion chamber, it causes catastrophic piston, valve, and potentially turbo damage costing €4,000+. The N47 has an updated design that is somewhat less prone to catastrophic fracture, but the flaps still seize from carbon deposits, causing rough idle, power loss, and fault codes. Preventive removal and blanking with plates costs €150-300 and is strongly recommended, particularly on the M47TU2. On the N47, the flap actuator motor can also fail, causing noise and limp mode. Actuator replacement costs €200-400. Many knowledgeable owners have already performed the swirl flap delete.
Turbo actuator failure
€500 - 1,8003 of 9
Electronic turbo actuator sticks or fails, causing sudden power loss and limp mode · more· less
The variable geometry turbocharger uses an electronic actuator that commonly fails on E90 320d models, particularly those built between 2005 and 2010. When the actuator sticks or fails, the turbo cannot regulate boost pressure correctly, resulting in intermittent power loss (the engine feels as though it has lost half its output) and limp mode. BMW does not sell the actuator separately from the turbocharger assembly. A specialist repair of the actuator alone costs €500-800. If the turbo internals are also damaged from running with a faulty actuator, full turbo replacement costs €1,200-1,800 including labor. Aftermarket remanufactured actuators are available for €200-350. Regular driving at varied engine loads and avoiding extended idle periods helps keep the actuator moving freely. On the M47TU2, oil starvation from a clogged crankcase ventilation valve is a common contributing factor to turbo failure.
DPF clogging
€300 - 2,0004 of 9
Diesel particulate filter blocks with soot if the car rarely reaches highway speeds · more· less
Both the M47TU2 and N47 engines are equipped with a DPF that requires regular extended drives at highway speeds for passive regeneration. A failed or stuck-open thermostat is a common underlying cause on the E90, preventing the engine from reaching the 75+ degree coolant temperature needed to trigger regeneration. Cars driven predominantly on short urban trips accumulate soot faster than the DPF can burn it off. Symptoms include the DPF warning light, reduced power, and eventually limp mode. A forced regeneration at a workshop costs €150-300. Professional DPF cleaning runs €300-500. If the filter is beyond cleaning, replacement costs €1,200-2,000 including labor at a BMW dealer, or €800-1,500 at an independent specialist. Checking and replacing the thermostat (€200-350) is often the first step before addressing the DPF itself.
EGR valve clogging
€300 - 8005 of 9
Exhaust gas recirculation valve clogs with carbon, causing rough idle, hesitation, and fault codes · more· less
The EGR valve accumulates carbon and soot deposits over time, particularly on cars driven mainly in city traffic. Symptoms include rough idle, slight hesitation under acceleration, increased fuel consumption, and engine management warning light. N47 cars from August 2010 production onward fall within BMW's expanded EGR cooler campaign for internal leaks that can cause a fire risk, with model-specific periods inside that range. Cleaning the EGR valve at a workshop costs €150-250. If the valve needs full replacement, expect €400-600 at an independent shop or €600-800 at a BMW dealer. On N47 cars inside that production window, verify with the VIN that the EGR cooler campaign has been completed before purchase. Regular highway driving helps keep the EGR system cleaner.
Oil leaks (valve cover and oil filter housing gaskets)
€400 - 1,0006 of 9
Gaskets harden with age and heat cycling, causing oil seepage from multiple locations · more· less
Oil leaks are among the most common issues on the E90 320d, particularly on cars over 10 years old. The valve cover gasket, oil filter housing gasket, and oil pan gasket all deteriorate from repeated heat cycling. The valve cover gasket typically starts weeping between 80,000-130,000 km, with oil dripping onto the exhaust and producing a burning smell. The oil filter housing gasket can also leak coolant since it incorporates a heat exchanger. Valve cover gasket replacement costs €300-500 at an independent shop, while the oil filter housing gasket adds €200-400. Addressing both during one service visit saves significant labor cost. The oil pan gasket is less common but more expensive due to access requirements (€300-500 additional).
Crankcase ventilation valve (CCV) failure
€150 - 4007 of 9
CCV valve clogs causing excess crankcase pressure, oil leaks, and turbo damage · more· less
The crankcase ventilation system on both the M47TU2 and N47 clogs over time, typically between 100,000-180,000 km. When the CCV valve fails, crankcase pressure builds up, pushing oil past seals and gaskets. This causes oil leaks, increased oil consumption, white smoke from the exhaust, and accelerates turbo seal wear. On the M47TU2, a clogged CCV is a primary contributor to turbo failure. The CCV valve and hose kit costs €80-150 for parts, with labor adding €100-250. This is considered essential preventive maintenance. Upgraded silicone hoses are available and offer significantly longer service life than the original rubber components.
High-pressure fuel pump failure (N47)
€800 - 2,5008 of 9
Cam-driven HPFP fails causing hard starting, power loss, and potentially contaminating the entire fuel system · more· less
The N47 engine's high-pressure fuel pump can fail due to internal wear, contamination from skipped fuel filter changes, or reduced lubricity in modern ultra-low sulfur diesel. When the pump fails catastrophically, metal debris can contaminate the entire fuel system including injectors, fuel rail, and lines, turning a €600-800 pump replacement into a €2,000-2,500+ fuel system overhaul. Symptoms include difficult starting, engine surging, and fluctuating idle speed. Regular fuel filter replacement (every 20,000-30,000 km) is the most effective preventive measure. This issue is less common than the timing chain problem but more expensive when it occurs due to secondary contamination damage.
Glow plug controller failure
€150 - 4009 of 9
Glow plug control module fails from heat exposure, causing difficult cold starts and DPF problems · more· less
The glow plug controller mounted under the intake manifold is exposed to significant heat and can fail, preventing one or more glow plugs from functioning correctly. Symptoms include extended cranking in cold weather, rough idle when cold, and incomplete DPF regeneration leading to secondary DPF issues. The controller itself costs €40-100. Individual glow plugs are €20-40 each. The main expense is labor, as the controller is located under the intake manifold and is difficult to access. Total replacement cost including plugs and controller runs €150-400 at an independent shop. It is recommended to replace both the controller and all four glow plugs at the same time.
Engine choice defines the ownership experience
The E90 320d's reliability depends heavily on which engine is fitted. The M47TU2 (2005-2007, 163 hp) is a fundamentally solid diesel with manageable issues: swirl flap deletion, CCV maintenance, and turbo longevity are the main concerns. The N47 (177 hp from September 2007, 184 hp from spring 2010, 163 hp in the EfficientDynamics Edition) adds the well-documented rear-mounted timing chain weakness, which is the single biggest risk factor on this car. Cars built before the January 2009 parts change are most severely affected, and chain work is still specified for later N47T engines. Both engines share turbo actuator, DPF, EGR, and oil leak concerns. With short oil change intervals (10,000 km maximum), regular highway driving, and proactive maintenance, many E90 320d models reach 200,000+ km. Always identify the engine before buying and budget accordingly.
Service history
Complete BMW dealer or specialist records essential. Verify oil changes every 10,000 km maximum, not the extended 25,000 km BMW long-life interval.
Tires
Check tread depth, age (date codes on sidewall), and uneven wear. Rear tires wear faster on RWD models.
Cold start
Must start engine completely cold. Listen for timing chain rattle (N47), turbo whine, and observe exhaust smoke colour.
Test drive
Minimum 30 minutes including highway speeds. Check for full boost, smooth power delivery, and no warning lights.
Specific for this vehicle
Identify the engine: M47TU2 or N47
Do not treat March 2007 as a fixed changeover. The 177 hp N47 went on sale in September 2007; from spring 2010 the standard car used a 184 hp N47 and the EfficientDynamics Edition a 163 hp version. Check the engine code in the vehicle documents against the build date on the door jamb sticker. The N47 carries the timing chain risk; the M47TU2 does not.
Cold-start timing chain rattle (N47 only)
Start the engine completely cold and listen carefully for a metallic rattling from the rear of the engine during the first 30 seconds. A rattle of anything from one to thirty seconds indicates chain and tensioner wear requiring immediate attention.
Check for turbo actuator issues under load
During the test drive, accelerate firmly from low RPM in a high gear. Any hesitation, sudden power loss, or limp mode warning indicates turbo actuator problems.
+ 4 more checksShow less
Verify swirl flap status
Ask if swirl flaps have been removed and blanked. If not, request a diagnostic scan for swirl flap fault codes. This is particularly important on M47TU2 models where catastrophic flap failure is a known risk.
Inspect for oil leaks underneath
Look under the engine for oil drips, especially around the valve cover, oil filter housing, and oil pan. Oil on the exhaust produces a burning smell from the engine bay.
Check DPF condition via diagnostics
Ask for a diagnostic scan showing DPF soot loading percentage. Soot above 40% indicates a car driven mainly on short trips. Verify the thermostat is reaching 75+ degrees coolant temperature.
Verify EGR cooler recall completed (N47)
BMW's expanded EGR cooler campaign covers N47 production from August 2010 onward, with model-specific periods. Contact BMW with the VIN to confirm whether it applies to this car and has been completed.
Recalls and Technical Service Bulletins
EGR cooler internal leak with fire risk (N47 diesel engines built from August 2010, model-specific periods)Critical - verify completed
Timing chain technical action going beyond tensioner replacement (N47 18d/20d/23d built 1 February 2007 - 24 December 2008)Verify completed
Takata airbag inflator replacement (2005-2011, applies to cars with aftermarket steering wheels)Verify completed
Blower regulator connection (October 2004 - July 2011 production)Verify completed
B+ battery connector, UK campaign (petrol and diesel 3 Series built March 2007 - September 2011, VIN-dependent)Verify completed
Contact BMW with the VIN to confirm which campaigns apply to a specific car and whether they have been completed. The EGR cooler campaign addresses a fire risk but covers N47 production from August 2010 onward with model-specific periods, so it does not reach every N47. The timing chain technical action covers cars built between 1 February 2007 and 24 December 2008 and involves more than the tensioner. The B+ battery connector campaign was run in the UK and depends on the VIN.
Warranty Status
Factory warranty (2 years)Expired on all E90 320d models
Rust perforation warranty (12 years)Expired on all models (latest cars expired 2023)
Extended warranty availabilityThird-party only, limited for this age
All E90 320d models are well outside their original 2-year factory warranty and 12-year rust perforation warranty. Extended warranty coverage from third-party providers may be available but is increasingly limited and expensive for cars of this age. Budget for self-funded repairs.
Sources: Research draws on model-specific owner forums and owner communities, recall information from official authorities, German automotive press, and multiple workshop cost references cross-checked against each other.
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.
