The multi-part crank hub is held in place only by the clamping force of the crankshaft bolt and the friction between the mating surfaces. There is no key and no splined connection, so there is no mechanical constraint either. Under sustained high load, at high torque, the hub can slip, and the valve timing then loses its reference to the crankshaft.

The symptom is a drivetrain malfunction message on the dashboard, the engine management light, uneven running, difficult starting and limp mode. A camshaft or crankshaft timing code appears in the fault memory, and the two together are the most telling. If the timing moves far, the valve and the piston can meet, and that is internal engine damage.

Not every example is affected: many engines run without trouble throughout. The risk is higher on tuned and track-driven cars, because the load there is greater, but standard condition does not rule it out either. The fault occurs from 60 000 kilometres.

The solution is a pinned conversion: precisely drilled pins give a mechanical connection in place of the friction. The part is around 800 pounds, and 1950 pounds with fitting. One thing is worth knowing: this fault belongs to the S55 engine, and the N55, the B58 and the S58 are not affected.