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I am the owner of a BMW x6 4.0d with a 306 horsepower N57 engine.
Recently, the fans have been intermittently operating and the temperature has been fluctuating abruptly between 90 and 112 degrees. It is not increasing beyond this point. However, this issue only occurs when I consistently drive at a speed of 1400-1700 rpm with the cruise control on. During acceleration or while the engine is idle, the temperature remains at a typical level of 90 degrees. I would like to inform you that I have just acquired a new thermostat, an additional new pump, and a new temperature sensor. The vehicle is not experiencing any coolant loss and there is no build-up of pressure in the expansion vessel.

Greetings, everybody! A month ago, my 2013 X5 with 66k miles displayed a high temperature warning, prompting me to take it to the dealership for a diagnostic assessment. They replaced my coolant pump for a total cost of $2000. Within a month, the fan begins to operate sporadically, emitting a very loud noise, often occurring after driving for around 10-15 minutes. Therefore, I returned it to the dealership. The experts were unable to determine the precise source of the malfunction that triggers the fan to operate at maximum speed. The service adviser proactively contacted BMW via email to seek guidance. BMW replied, indicating that the problem could be caused by the occasional failure of the power supply to the coolant pump. Consequently, they advised replacing the engine harness and the IVM, and then conducting a recheck. The price will amount to $2500.

Is BMW's advice accurate? Should I get the water pump inspected?

Inadequate coolant levels may result in engine overheating, causing the fan to operate at elevated rates in order to cool the engine. Ensuring the coolant level is correct is crucial for achieving effective engine cooling.