[Merlino31]

Goodmorning,
I have noticed a strange noise in my f31 07/2014 with 88k km 6MT.
I've always double pressed the power button to shut off the engine and radio before get out.
Now I coded the iDrive shutting down with the driver's door opening.
When I open the door everything shutts off and I can hear a Clunk from the engine bay...a sound similar to the relay in the rear which cuts power to the fuel pump after about 20 second from the shutting off.
In my opinion everything is normal but I want to know what makes this noise.
Any idea?

[MacLover38]

Hello,
I have this on mine 320d 8AT too, I think it's completely normal sound. I thought it could be something when the car is about to go to the electrical "sleep mode".

[Chigurh]

I also hear this clunk in my 328i shortly after shutting off but that has always been there. Don't know what makes it really.

[Eddamoo]

Yep its probably normal, my 330d and most other cars have done the same in the last decade or so.

In my experience its the Anti Shudder Valve. This is a throttle plate place close to the inlet manifold that chokes the engine on shutdown so it stops quickly. This prevents the car shuddering over extra engine compressions (which can be aggressive on diesel engines particularly).

Once the engine has stopped and the vacuum has stopped, the ASV springs back open with a loudish clunk.