BMW 30d
Modular straight-six diesel with up to 340 hp in the M version. Extremely smooth and torquey; DPF and SCR catalytic converter are the main wear points.
Diesel Torque
Inline-six diesel with punch — the M40d is particularly impressive.
Engine Weaknesses 5
EGR cooler can fail and allow coolant into the intake tract. Documented cases of engine damage shortly after EGR cooler replacement.
Symptoms: Coolant loss, white smoke, engine check light, overheating
Early B57 models (from about 2015/16) show chain elongation with rattling noises on startup. Timing chain replacement requires engine removal. Repair costs comparable to the N57. Significantly rarer from 2018 models.
Symptoms: Metallic rattling on cold start, especially at low temperatures; subsides after warm-up; in extreme cases engine stumble
Bearing damage occurs in the bi-turbo system at higher mileage. Turbine blades can break off and cause engine damage. Frequently encouraged by insufficient oil change intervals.
Symptoms: Whistling or howling under load; blue exhaust smoke; power loss; MIL; in extreme cases sudden power loss from turbo failure
The EGR valve cokes up with frequent short-trip driving and becomes stiff. Stumbling on cold start is characteristic. BMW carried out a voluntary service action.
Symptoms: Stumbling and hesitation on cold start until the engine warms up; power loss; 'Drivetrain malfunction' message; black smoke; EGR valve fault
NOx sensors and SCR dosing unit fail after about 100,000 km or through AdBlue crystallisation. Fault code 26F500 is typical. BMW repairs often cost 2,000–4,000 EUR as entire systems are replaced.
Symptoms: MIL with message 'AdBlue system faulty' or 'Emission system fault'; fault code 26F500; engine runs normally but warning persists
Vehicle Weaknesses 7
Signal faults in the IBS electronics can cause hydraulic brake assistance to fail. ABS and DSC then unavailable. Approximately 1.5 million vehicles worldwide affected.
Known G01/G02 issue: at low speeds up to around 70 km/h, different steering forces left and right. Cause is missing EPS calibration after wheel alignment.
Seal issues on the panoramic roof cause wind noise at motorway speeds. Water ingress through blocked drainage channels also documented. Revised seal available.
Automatic opening via foot gesture under the tailgate works unreliably. Sensor faults or software issues; dealer updates usually help in the short term.
The iDrive 7 system occasionally freezes or reboots. CarPlay connections drop. Software updates fix most issues short-term but new ones appear.
Many owners find Sport mode unacceptably harsh and Comfort mode offering no real comfort. Damper replacement needed at higher mileages.
Early G01 units from US production are prone to interior and boot creaks and rattles. South African production has better quality. Now largely improved.