BMW Repair Questions? Ask a Mechanic for Answers ASAP
It would be my pleasure to assist you with this.
I am familiar with this problem you are describing on your N52 engine.
I do not think the other expert was familiar with your problem. On your vehicle you have an electrical water pump. When this begins to fail it will give you the temperature warning and the electrical fan will come on high. Sometimes even just restarting the vehicle can correct this for a short time.
The problem is internal in the electrical water pump as the speed is monitored by the engine control unit. When it identifies a problem the overheat warning will be displayed.
I have a video describing this on an x3 with the same style water pump.
I hope this information is helpful. Please accept this answer by pressing the ACCEPT tab. You will not be charged again but this will transfer your deposit for my assistance today. If I can help you further please let me know. If I can help you in the future please ask for Roger. Thank you.
Here is the link for the same situation you described that I have made a video on: