BMW M8

Revised connecting rod design compared to S63TU with 8 additional oil drillings. Despite this, documented failures exist: a workshop case study shows an F90 M5 with connecting rod and crankshaft damage. The F90 sees the problem less often than the F10.

Symptoms: Noticeable knocking from the engine, metal particles in the sump and filter housing, crankshaft damage as a consequence of delayed diagnosis

The high-pressure fuel pump can fail at high mileages or with aggressive use. Fuel pressure drop causes noticeable power loss and can secondarily damage injectors and turbochargers.

Symptoms: Power loss under high load, hard starting, fault code fuel pressure too low (P0087), stumbling at full throttle.

The turbochargers mounted in the V-valley are subjected to extreme radiant heat. Coolant lines and connections can crack through thermal cycling. Allow an adequate cool-down phase after full-load driving.

Symptoms: Coolant loss in the turbo area, coolant smell after driving, steam from the bonnet, reduced boost pressure.

Electric wastegate actuators on both turbo banks can fail — bank 2 more often. BMW has issued a warranty extension to 15 years/150,000 miles. Cost: €800–€3,500.

Symptoms: Engine fault message, power loss, limp mode activation, boost pressure regulation fault code (typically 4506E/4506F), drivetrain warning in instrument cluster

VANOS solenoids can generate fault codes despite the revised design. The S63T4 uses four solenoids — oil deposits are a common cause. Cleaning or replacement usually resolves the issue. The VANOS gear is a secondary cause if solenoid replacement does not help.

Symptoms: MIL activation, limp mode, fluctuating engine output, rough running at certain rev ranges

Same mechanism as on the S63: V-valley heat hardens valve stem seals. Workshop service £3,540–£4,140 with genuine parts (GND Motors). Typically appears from 120,000+ km.

Symptoms: Blue smoke on acceleration after an idle period, measurably increased oil consumption, sooty spark plugs

The S63B44T4 places heavy demands on the ignition system through high boost pressure and temperatures. A single failed coil signals further failures — standard practice is preventive replacement of all 8 coils at once.

Symptoms: Misfires, rough idle, power loss, fault codes P0300–P0308, noticeable vibration under acceleration.

The S63B44T4 generates extreme heat in the V-valley. Thermostat and plastic expansion tank are prone to premature wear at higher mileages. The overheating risk on failure is considerable.

Symptoms: Coolant loss without visible leak, temperature gauge fluctuates or rises too high, coolant level warning, steam from engine bay.

iDrive 7 system freezes, shows a black screen, or becomes unresponsive. Software restarts help temporarily.

Adaptive shock absorbers can be locked at maximum damping hardness through sensor faults or wiring corrosion.