One problem related to loud engine noise has been reported for the 2010 BMW X5. The most recently reported issues are listed below.
While driving a short distance at low speeds through a city, a yellow warning message came onto the screen, alerting me that the vehicle was overheating and to drive carefully. Only seconds later a second warning message came onto the screen, this time red, telling me that the engine has overheated and I need to stop driving immediately. As I slowed I could hear a loud fan noise and began to smell burning plastic. I immediately contacted a technician to schedule a repair. I was told it is a very common problem with the coolant pump, and upon further investigation, I discovered that it has led to very costly repairs on top of potentially dangerous situations. I even discovered that there may be a class action lawsuit for the faulty parts, and in some models have been recalled. I contacted BMW directly and they told me my vehicle was not eligible for any extended warranty or recall.