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N46B20
2.0L Petrol
N-series • N46 family • 2004–2011
62%
Engine Reliability
The N46 is an evolution of the N42, introducing Valvetronic variable valve lift. Generally reliable but the eccentric shaft sensor and timing chain are known weak points. Widely used in entry-level BMWs.
2.0L
Displacement
I4
Layout
129–170 hp
Power
180–210 Nm
Torque
Petrol
Fuel
Naturally aspirated
Aspiration
Technology & Features
Fuel SystemPort injection
ValvetrainDOHC 16-valve, Valvetronic
Used In 1 Application
2
Known Issues
1
Critical
2
Wear Items
1
Applications
Known Issues – N46B20
high
Eccentric Shaft Sensor Failure Common (>40%)
The Valvetronic eccentric shaft sensor fails, causing limp mode and rough idle. Engine warning light illuminates.
Typical Mileage
60,000–120,000 km
Est. Repair Cost
€200–€400
DIY Friendly
✓ Yes
Rough idleLimp modeEML warning light
critical
Timing Chain Wear Common (>30%)
Timing chain stretches over time, causing rattling on cold start. If not addressed can lead to catastrophic engine damage.
Typical Mileage
80,000–150,000 km
Est. Repair Cost
€1,500–€3,000
DIY Friendly
✗ Specialist
Rattling on cold startRough runningCheck engine light
Wear & Maintenance – N46B20
Spark Plugs
Every 60,000 km
Replacement Cost€80–€150
Wear Factor60%
Valve Cover Gasket
80,000–120,000 km
Replacement Cost€150–€300
Wear Factor70%
Applications (1)
Transmissions (2)
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6-Speed Manual (Getrag)
Getrag • 6-speed manual • 2003–2019
Getrag 6-speed manual used across a wide range of BMWs. Different models handle various torque capacities. Known for precise, mechanical shift action. The GS6-53DZ handles up to 500Nm (used with 335i/M135i).
Known Issues2
medium
2nd Gear Synchro Wear Moderate (~20%)
Second gear synchros can wear, especially on higher-torque applications, causing grinding on fast 2nd gear shifts.
Typical Mileage
100,000–180,000 km
Est. Repair Cost
€800–€1,500
DIY Friendly
✗ Specialist
Grinding into 2nd gearDifficulty downshifting to 2nd
low
Clutch Release Bearing Noise Moderate (~25%)
Clutch release (throw-out) bearing develops a chirp or whine when clutch is depressed.
Typical Mileage
80,000–150,000 km
Est. Repair Cost
€400–€800 (usually replaced with clutch)
DIY Friendly
✗ Specialist
Chirping with clutch pressedWhining noiseVibration in pedal
Wear Items
Clutch Assembly
100,000–180,000 km
Replacement Cost€700–€1,500
Wear Factor55%
Dual Mass Flywheel
150,000–250,000 km
Replacement Cost€500–€1,000
Wear Factor45%
Transmission Fluid
Every 80,000 km
Replacement Cost€50–€120
Wear Factor30%
Fluid TypeMTF-LT-4 / MTF-LT-5
Service IntervalLifetime fill (recommended every 80,000 km)
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6-Speed Automatic (ZF 6HP)
ZF • 6-speed automatic • 2003–2014
The ZF 6-speed is an excellent torque-converter automatic used across BMW, Audi, Jaguar, and others. Smooth, responsive, and very reliable when serviced properly. The 6HP26 handles up to 600Nm. Mechatronic (valve body) issues can occur at high mileage if fluid has never been changed.
Known Issues2
high
Mechatronic Unit Failure Moderate (~20%)
The mechatronic unit (integrated valve body and TCU) can fail, causing erratic shifting, limp mode, or complete transmission failure. Usually caused by degraded fluid.
Typical Mileage
120,000–200,000 km
Est. Repair Cost
€800–€2,500
DIY Friendly
✗ Specialist
Harsh shiftingLimp mode (stuck in gear)Warning lightNo drive
medium
Torque Converter Shudder Moderate (~20%)
Torque converter lockup clutch develops a shudder at light throttle / highway cruising.
Typical Mileage
100,000–180,000 km
Est. Repair Cost
€1,000–€2,000
DIY Friendly
✗ Specialist
Vibration at 60-100 km/hShudder under light load
Wear Items
Transmission Fluid & Filter
Every 60,000–80,000 km
Replacement Cost€250–€500
Wear Factor50%
Transmission Pan Gasket
With fluid service
Replacement Cost€30–€60
Wear Factor40%
Fluid TypeZF Lifeguard 6
Service IntervalEvery 60,000–80,000 km (BMW claims lifetime)