Many problems involve accessories such as faulty power-window regulators, sticky sunroof rails and unglued door seals on coupes. Suspension control-arm bushings may need replacing as early as 60,000 kms. A major problem is the VANOS variable-valve-timing unit that craps out under 100,000 kms due to poor O-ring sealing materials drying up as well as cam sensors failing, leading to loss of torque and a rattling sound above 2000 rpm. The cooling system is known to fail catastrophically due to a disintegrating water-pump bearing, leading to immediate coolant loss and overheating. Additional wear items in the cooling system are the plastic electric thermostat and the water reservoir, which require attention every 100,000 kms. Early models had problems with cracks appearing in rear subframe and luggage-trunk floor, but while repair is expensive, this issue doesn't really affect those who don't abuse the car on a racetrack. Cars built between 2002 and 2004 had a recall for failing ignition coils. BMW-recommended time between oil changes is well beyond 20,000 kms, while early models had "lifetime" gearbox fluid, both being rather dubious claims, as these may cause problems after warranty is over.