My new 2014 Compass makes a low "metal rattling" sound (best way I can explain it) when I turn the car off. It SOUNDS LIKE (not saying this is what it is) a small metal ball that rocks around (unheard) while the car is on, and then when the car is shut off it rattles to a standstill over the course of not even 2 seconds.
When I first picked up my new 2014 Compass a few months ago, I don't remember hearing that. It's possible I just wasn't paying attention. But over the course of a few weeks, I started to notice it. And now, it's been a few months. But no mechanical issues stemming from this sound, as far as I can tell.
I mentioned it to Jeep when I brought it in for standard maintenance, and they say it's a natural part of the processes as the car shuts off. (They gave me a name for the part that's doing it -- I can post it here when I get my hands on the service printout.) They said it's not a problem with the car.
You may get used to hearing rattles coming from your compass. I have a 2012 model and have had it back with the dealer now 4 times so far to fix different rattles. I currently have a strange rattle / grating sound coming from the front end when I steer at slow speed. It's booked back in for this Thursday to see what the noise is
Finally had someone else turn the car off so I could listen closely...
The sound comes from the backside of the engine compartment. With the hood up, I could hear it coming from the area behind the engine block. Loud and clear... a metal knocking sound "clanking" rapidly maybe 5 or so times right after shutdown, and then silence. Every single shutdown.
That is the top of your exhaust manifold. that shiny stuff on the fire wall is heat shielding. so yeah, it sounds like a heat shield rattling. you have a 2014, which would mean its under warranty, its easy to duplicate, I would take it to the dealer, and make sure the service writer is standing there, and can hear the sound and tells you he hears it, and that should get it fixed quick. Heat shields, because they take a lot of heat expand and contract, and so are held on by lose fittings, that come off easily.