BMW M760Li
The N74B66 is an N74B60 with more stroke — 6.6 instead of 6.0 litres; otherwise identical architecture. Two DME control units, two high-pressure pumps, two turbochargers. The power increase to 585 or 609 hp comes not from higher boost but from the larger displacement — the engine runs more relaxed than comparably powerful six-cylinders. 850 Nm from 1,550 rpm available immediately. In everyday use barely audible; on the motorway almost frighteningly fast. The solenoid injectors of the later models are significantly more reliable than the first piezo units. Observe all service intervals strictly — short oil changes (maximum 15,000 km) and cool-down after hard use are not a recommendation but a requirement for BMW's last V12.
M760Li V12 — Silent Brutality, 850 Nm from Idle
850 Nm at 1,550 rpm — acceleration feels like a natural force, not a sports car event. No harshness, no turbo lag, no acoustic drama. Inaudible daily, at full throttle the valves open and the V12 speaks with an authority no V8 can touch. BMW's last V12 — no successor planned.
Engine Weaknesses 11
The bi-turbochargers of the N74B66 show bearing wear at higher mileages, especially with irregular oil changes. Failing to let the engine cool after full-load driving accelerates bearing wear considerably.
Symptoms: Whistling or whining under acceleration, bluish exhaust smoke, power drop, boost pressure faults.
Early N74B66 units (2016–2018) used piezo injectors prone to internal leakage. Conversion to solenoid type recommended. Mixing old and new injectors is not permissible — full set required.
Symptoms: Rough running on individual cylinders, misfires, increased fuel consumption.
The elaborate cooling system of the N74B66 V12 uses multiple thermostats and an electric auxiliary water pump. Plastic thermostat housings and seals fail with age. Coolant loss is increasingly common.
Symptoms: Coolant level drops without visible leak, engine temperature warning, steam from under the bonnet.
The N74B66 V12 develops increased oil consumption through worn valve stem seals at higher mileages. The complexity of the V12 makes this repair particularly labour-intensive and expensive.
Symptoms: Blue smoke on overrun or after idling, dropping oil level, oil smell from exhaust.
Same issue as the N74B60: the coolant crossover pipe seal between cylinder banks can fail. Coolant loss without visible external leak. Repair requires intake manifold removal.
Symptoms: Dropping coolant level without visible leak, sweet smell, rising temperature.
Wastegate actuators on both turbochargers develop play with mileage. Metallic rattling at mid-range revs. If left untreated, uncontrolled boost build-up and turbine damage are possible.
Symptoms: Metallic rattling in the mid rev range, boost pressure regulation fault code, irregular power delivery.
Electrically driven water pump with known early failure tendency from 80,000 km. Overheating damage on a V12 is particularly costly — preventive replacement recommended.
Symptoms: Slowly rising coolant temperature, warning light, limp mode.
G11 air suspension is wear-prone just like the predecessor. Compressor and air springs age. BMW coding required on replacement — not possible without a diagnostic tool.
Symptoms: Car sags to one side or at the rear, ride-height error message, unsettled ride.
Twelve cylinders each with one coil and one spark plug. High maintenance effort; oil intrusion through cam cover gaskets accelerates failures.
Symptoms: Misfires, rough running, engine warning light
Both cam covers tend to leak with age. Oil gets into the spark plug tunnels and destroys ignition coils prematurely. With 12 cylinders this becomes a major maintenance job.
Symptoms: Oil smell, oil visible in spark plug tunnels on plug change, repeated ignition coil failures.
Transmission oil cooler lines can leak with age. Transmission oil loss leads to increased wear. Observed at higher mileage.
Symptoms: Oil drops under the car centrally, rising transmission temperature, overheating fault code.
Vehicle Weaknesses 16
Wiring harness problems or CAN bus faults cause fault messages across many control units simultaneously.
The PHEV system has no alternator. A fault in the SME module opens the contactors and the 12V battery discharges while driving.
Air bellows become porous from around 100,000–150,000 km; the compressor overheats from frequent pumping and fails. Car sags on one side or completely.
Signal fault in the motor position sensor can deactivate hydraulic brake assist. Approximately 1 million vehicles worldwide.
Recall KBA 16187R: a potentially misrouted cockpit wiring harness can be damaged during cabin filter replacement. A short circuit can cause smoke or fire — 337,374 vehicles worldwide affected.
G11 sags unevenly at all four wheels overnight. No fault code stored.
NOx sensor upstream of the SCR catalyst fails. Complete tank replacement costs 2,500–3,000 €.
Blocked or porous panoramic roof drain tubes channel water into the cabin instead of outside. Water collects in the headlining and runs toward the battery or control units.
Driver assistance systems on the G11 (lane keep assist, blind spot warning, junction assistant) malfunction frequently and require software updates or camera reinitialisations.
Faulty comfort access system draws continuously elevated current and drains the battery.
The interior door opening button integrated into the diamond light strip fails and no longer illuminates. Climate controls on the same side can also fail simultaneously. BMW replaces the entire light strip — approximately 4 weeks lead time.
Heavy luxury saloon with large brake discs. Surface rust after standing causes squealing.
Over-the-air updates can cause malfunctions: eSIM loses connection, settings reset.
The i7 shows significant range loss in cold conditions due to battery thermal management.
The G70's integrated eSIM module frequently loses connection at vehicle startup. BMW addressed the issue with software update 11/2023.42; improvements confirmed by several owners.
Soft-close doors don't retract reliably; comfort exit function stops working after OTA updates. Various body electronics functions show sporadic failures.