Hi, it's been -20 -25 celcius here lately and I noticed that when I drive with the car really cold, there's a short metallic whine around 2-2.5k rpm. Its like its about to change gears and then I hear a slight EeeEEeE metal whine noise or chirp, or whistling,, hard to explain. Lasts a few secm does it for a couple of minutes until the car has heated, and then gone.

What could be causing this? Seems related to engine rev and gears

 

-20 -25 celcius

 

Sounds like that old timing chain again there's plenty of post out there on this one

 

-4 to -13 degrees Fahrenheit

Maybe it's just the extreme cold, do you park outside, what oil do you use, wait until it goes back to normal and then see if the noise is their on start up

 

I think you should start warming up your car a bit. Just run out 5 mins before you leave and warm it up. then see if you have these issues. Cold temps do a number on your car, so I suggest warming up and seeing if the issue seems to fade a bit?

 

let her warm up and see if it's still there

there is a reason why high end bmv models have their speedo adjust the redline mark according the engine temp.

 

not to get off topic but I thought BMW just programed the ECU to not shift or rev past a certain RPM until the car has reached operating temp

 

When its that cold out and your car has been sitting for a long time (overnight) its not uncommon to hear a whine initially when you start your car. All my cars have done that in the winters, and it eventually dies down as your car warms up (usually 1 min it will stop whining).

If you can plug your car in, it will help out a lot to prevent the whining and its a lot better for the car.