Diesel engine turbo pipes can collapse.
EGR thermostat fails and won't let DPF regenerate
4.4-litre V8 can suffer coolant loss; expensive to fix
Oil leaks from cam covers and plastic gearbox sump pan
Replacement discs and pads are expensive from BMW
Run-flat tyres give a harsh ride and poor refinement
Bilstein dampers from BMW are £700
Body
Sunroof can squeak
Headlight bulbs are expensive to replace
Make sure Convertible's fabric roof latches into place smoothly
Rear seats cramped for adults
No standard cupholder is irritating
iDrive can fail and is pricey to rectify, but updates are available to make it more modern to use
Check for damp carpets as a sign of blocked bulkhead drain holes that can cause electrical faults
Use a battery conditioner if leaving the car idle for longer periods.