Hi all,

my 2018 Sportbrake (3.0L S/C) with 44k and no other issues (no MIL, no leaks, no driving issues) Is making the following noise every time I shut it down.

It's a long howl/muffled whine, that changes pitch, then it is followed by an abrupt and louder clunk. The clunk sounds like a flap or diaphragm opening/closing, and the howl reminds me of wind instrument, similar to a vac leak or air leak coming from a tube or reservoir. Curious if anyone has had this noise or has any ideas on what it might be. My local dealer can't take the car in for 2 weeks, so in the meantime, I am stuck living with it and wanted to see if anyone had thoughts. I will of course update this thread once I learn of the issue.

My best guess is the vacuum pump down my crank pulley? and the noise is traveling up through the plastic hardliner near the cowl. But this is alas, only a guess.

Video here:

 

Weird. Absolutely weird. Sorry but I'm unable to help.

 

Got the car back today from dealer - diagnosed as a bad PCV valve. Leak was causing a whistle noise as the engine vacuum slowly decreased after shut down. The car also had codes P0505-22 (soft, no CEL) in the system per the paperwork.

The loud Clunk noise at the very end can still be heard, but the howl is gone.

 

Congratulations! I'm happy to hear that the fix was simple and inexpensive.