BMW 520d
Widely used four-cylinder diesel with common-rail injection. Notorious timing chain issue — the chain sits on the gearbox side and elongates with irregular oil changes. Early replacement recommended.
Timing Chain Roulette
Every mile could be the last — the infamous timing chain makes the N47 a permanent nail-biter.
Engine Weaknesses 6
The N47D20 is notorious for its serial timing chain defect. The rear-mounted timing chain stretches and plastic guide rails break. Chain breakage causes total engine failure. Affected: build years 2007–2015.
Symptoms: Scraping or rattling noises on cold start from the rear of the engine. The damage often gives no acoustic warning and occurs suddenly.
The N47 water pump fails prematurely. When it does the engine overheats, causing secondary damage to an already vulnerable engine. Preventive replacement is recommended.
Symptoms: Coolant temperature rises suddenly, coolant loss, engine warning light, in the worst case overheating damage.
The high-pressure pump can wear internally and introduce metal swarf into the fuel system. Rail, pressure sensor, and all injectors are affected — complete system replacement is necessary.
Symptoms: Engine goes into limp mode; will not restart; fault code "rail pressure too low"; in the worst case the engine no longer runs
The EGR valve becomes coked through soot deposits. Contamination accelerates with frequent short-trip use. The valve no longer opens and closes correctly.
Symptoms: Power loss, increased fuel consumption, rough idle, EGR system fault code in memory.
The DPF does not fully regenerate with frequent short-trip use. Soot mass exceeds 45 g, fault code 480A, active regeneration is blocked.
Symptoms: Increased fuel consumption (over 9 L/100 km); rough idling; engine warning light; exhaust smell; DPF fault codes 480A/481A
The dual-mass flywheel wears disproportionately quickly at high mileage with diesel use. BMW revised the pressure plate and clutch disc after 2009/2010 due to a known shudder problem.
Symptoms: Strong vibrations at idle and when pulling away; shudder during gear changes; banging noises at low rpm; no fault code
Vehicle Weaknesses 8
F11 Touring has optional air suspension, considered a weak point. Failed air bellows or compressor causes the car to sag. MOT also flags drive shafts and springs.
The timing chain in N47 diesel and N20 petrol engines stretches prematurely. Rattling on cold start is the warning sign. If the chain jumps a tooth, engine damage results.
The wiring harness between the engine and gearbox control unit can drop onto the hot DPF. Insulation melts, a ground fault generates over 38 simultaneous fault codes and puts the car in limp mode.
On the N57, turbocharger oil return lines leak; crankcase and cam cover gaskets are also affected. Oil puddles under the car possible.
A plastic coolant flange on the oil filter housing develops hairline cracks and loses coolant. Mainly affects N47 diesel variants. The hairline crack is barely visible to the naked eye.
Leaking rear door liners can cause moisture damage in the footwell. Known weak point on F10/F11. Check for moisture inside when inspecting.
Older F10 models (up to around 2011) consistently pull to the right despite repeated wheel alignment. Usually only a full steering rack replacement resolves it.
The butyl adhesive bond on the acoustic foam in the rear doors separates. Rainwater can no longer drain to the door bottom and enters the footwell.