Can I please have the last seven of the VIN number as I would like to check your engine designation. There is a common issue that I know of but would like to verify if it applies to your vehicle. Thank you.
Thank you I did get the VIN. Just a few minutes while I look this up. Thank you.
With the N52 motor it is very common to have an intermittent failure of the water pump.
This will cause the same type of failure as the thermostat and I have found is usually the overall cause of the overheat warning. This problem does not always set fault codes so when a tech. reads the codes it may be misleading if the only code that is present is for the thermostat.
The fix is going to be to have the electronic water pump replaced.
I hope this information is helpful. Please accept and I wish you the best on your repair.
I have a video on a similar issue with the same engine that needed a water pump as well.
I have also seen some strange overheat problems from engine temperature sensors. This also should be removed and inspected for any physical defects.