BMW 330d

As mileage increases the timing chain stretches and the chain tensioner loses its spring force. Broken plastic guide rails send fragments into the oil sump, which can damage the oil pump.

Symptoms: Rattling or clattering on cold start that improves once warm. Further wear can lead to engine damage.

The swirl flaps in the M57TUD30 intake manifold become heavy from carbon and EGR soot deposits and can break off. Metal fragments enter the combustion chamber and destroy valves and pistons.

Symptoms: Sudden hard engine knock, power loss, blue smoke, engine will not restart.

On the M57TUD30 (build dates July 2012–June 2015), coolant can escape from the EGR cooler and ignite with soot deposits. BMW recalled approximately 300,000 vehicles across Europe.

Symptoms: Engine warning light, power loss, in rare cases smoke from the engine bay or vehicle fire.

The M57TUD30 biturbo retains the familiar swirl flap problems of the M57. Even the reinforced versions after 2004 can develop leaks or stick.

Symptoms: Hesitation under acceleration, intake tract noise, power loss at part throttle, swirl flap actuator fault code

Diesel injectors wear at high mileage. Diagnosis via cylinder balance test and return flow measurement. Individual injector replacement possible at around €450 including installation.

Symptoms: Rough running especially at idle, hesitation, increased fuel consumption, white or black smoke.

The M57TUD30 biturbo shows oil loss through the turbocharger shaft seals at high mileage. Oil accumulates in the charge air hose and intercooler.

Symptoms: Oil film in the charge air hoses and at the intercooler outlet, blue smoke at full load, increased oil consumption without visible external leaks

The M57TUD30 DPF clogs particularly with frequent short-trip driving, as regeneration cycles cannot complete.

Symptoms: DPF engine warning light, increased soot output, power loss especially on motorway runs

Faulty battery connectors on petrol models 2006–2011 and diesels 2009–2011 can cause complete electrical and engine failure. Recall was issued.

The electromechanical power steering (EPS) can fail sporadically without any fault codes — often due to corroded connectors or an overheated EPS motor. KBA recall for production years 2007–2012.

Rear suspension springs break frequently — a well-known MOT failure point. Especially E91 Touring and older examples from around 100,000 km. Spring seats also rust.

Water ingress through leaking door seals, blocked sunroof drain tubes, or faulty antenna brackets. Battery compartment and footwell can both be affected. Multiple causes.

Underbody, wheel arches, and rear subframe rust commonly reported on the E91 Touring. Door seal frames corrode on older examples; tailgate particularly susceptible.