One problem related to engine exhaust system has been reported for the 2004 BMW X3. The most recently reported issues are listed below.
1. No advance warning. 2. Failure of pcv valve system, with resulting immediate consumption of engine oil through combustion process. Engine stalls and vehicle is brought to complete stop. The failure has occurred three times in the past 3 years. 3. Pcv related hardware replaced in first incident, with claim that "redesign" would prevent recurrence. Same in second and third incident. This is not only an inconvenient problem, it is also safety related, as the problem can result in the vehicle being immobilized in traffic. It is also not an isolated problem, based on what BMW technicians and other mechanics have related.