1. Potential Problem -Electrical and steering rack have a potential problem, however if the user regularly maintain their car to an authorized workshop, the problem can be minimized.
   
2. -The fuel quality is also can be a problem, to reach top performance BMW engine required minimum RON 95 fuel, however lots of BMW owner in US fill their car with lower OCT fuel. Under specification fuel caused a lower performance and also increasing carbon deposits in cylinder head. The fuel consumption of 318i relatively higher than its competitor with the same engine displacement, around 1 ltr for 7 km for city driving and 1 : 9 for extra urban.
   
3. -The most common fault on the E46 3-Series is with the heater blower resistor. [Just changed mine last week. $100.44 + labor]The switch breaks, meaning the fan keeped running after turning the car off. Other say that the fan only work on its fastest setting. That did not happend to mine. Early 320d and 330d manuals could suffer warped clutch plates. Most will have been replaced, but listen for a scraping noise when releasing the clutch on low-mileage cars. Post-2000 cars have tougher clutches.
4.  -Thermostats can fail, so keep an eye on the temperature gauge. Make sure the ventilation fan works on all speeds, too.
5.  - Ignition Coils:These vehicles have exhibited an unusually high failure of ignition coils. There is one coil for each cylinder, located above the spark plug. The symptom is a misfire and setting the “Service Engine Soon” warning. When we read out the fault codes, we see “Misfire on cylinder X”. They seem to exhibit the symptom most frequently after the engine is fully warm.
6.  -Window Regulators: Several users have reported having one or more replaced under warranty. If the window stops moving or begins to make quite a bit of noise, do not continue to try to move it or the drive motor may also be damaged.

    7. -PCV Valve: The vacuum valve on these cars has a higher failure rate than the one on the previous 3 Series. Its failure causes rough idling and sets the Service Engine Soon light. If your engine starts to make a honking noise, like a small goose, this valve is the culprit.
  
8.  - Cam Position Sensor: The position sensor for the camshaft will go open, either intermittently or completely. If it fails completely, the engine won’t run. If intermittent, it will die, then restart, run for a while, and repeat the cycle. It usually sets the “Service Engine Soon” warning.