BMW , 3 Series , E46 Common Issues

Oil leaks from valve cover gasket (10-20% of vehicles)
Faulty oxygen sensors (8-12% of vehicles)
Worn out lower control arm bushings (6-10% of vehicles)
Rear main seal oil leak (5-9% of vehicles)
Transmission solenoid failure (4-8% of vehicles)
Coolant leaks from water pump or hoses (3-7% of vehicles)
Faulty VANOS solenoids (2-6% of vehicles)
Oil pressure sending unit failure (2-5% of vehicles)
Rear wheel bearing failure (1-4% of vehicles)
Front wheel bearing failure (1-4% of vehicles)
Crankshaft position sensor failure (1-3% of vehicles)
Faulty knock sensors (0.8-2% of vehicles)
Transmission torque converter slipping (0.5-1.5% of vehicles)
Ignition coil misfires (0.4-1.2% of vehicles)
Rear differential bearing failure (0.3-1% of vehicles)
Faulty fuel pressure regulator (0.2-0.8% of vehicles)
Alternator belt slip (0.2-0.6% of vehicles)
Oil pan gasket leaks (0.1-0.5% of vehicles)
Brake master cylinder failure (0.05-0.3% of vehicles)
Water in fuel system (0.02-0.2% of vehicles)