BMW 120d

The timing chain can stretch or the chain tensioner can fail. Compared to the N47 the M47 is considered more robust, but timing chain problems occur at high mileages and with neglected maintenance.

Symptoms: Rattling on cold start from the front of the engine, easing after warm-up. With heavy stretching, engine damage through chain jump.

The metal swirl flaps in the intake manifold work loose through carbon deposits and can break off. An ingested flap blade causes immediate total damage to valves and pistons.

Symptoms: Engine stumbling, sudden severe power loss, loud metallic noise from engine, engine failure.

The aluminium cylinder head of the M47TU tends to develop hairline cracks between valve seats and glow plug bores at high mileages. The cause is the different thermal expansion coefficient of the aluminium head and cast iron block.

Symptoms: White smoke from exhaust, rising oil level through coolant contamination, coolant loss without visible leakage.

The turbocharger of the M47TUD20 is susceptible to damage through oil starvation or oil sludging. A blocked oil separator increases crankcase back pressure.

Symptoms: Whistling noise under acceleration, power loss especially at higher revs, blue smoke under load

The exhaust gas recirculation valve carbons up over time and no longer opens/closes correctly. The coking accelerates especially with lots of short-trip/city driving.

Symptoms: Power loss, increased fuel consumption, rough idle, fault memory entry EGR.

The electromechanical power steering (EPS) can fail completely on 2007–2012 models. A recall was issued for certain production years.

Rear subframe is prone to severe corrosion from around 100,000 km, including through-rust. MOT failure possible. Repair often costs more than the car is worth.

Broken suspension springs and rusty spring perches are frequently flagged on the E87 per TÜV reports. Worn track rod ends are also a known defect. Affects both front and rear axle.

Rust forms on the tailgate particularly around the badges and rear wiper. Hemmed edges and hinges can also be affected.

Water enters through faulty door seals, blocked sunroof drains, or cracked body grommets, reaching the footwell and boot. Electrical damage possible.

Rubber bushings on the rear control arms lose their elasticity. Camber change and MOT failure possible. Replace both sides simultaneously.