I have a 2010 MCCs with about 2800 miles on her. I have noticed that after turning off the engine while still sitting in the car, I have heard a slight knock, seeming to come from the rear. Then I heard it again about 30-40 seconds later ... and this went on for a couple of minutes.

Does anyone know what this can be?

 

your gas tank pressure is equalizing(fart)

 

Boot Monkey!!

 

This is very common and you will find that if you got out of the car and climbed underneath it you would hear it coming from the exhaust. There are many threads on this subject.

 

Mine does that. I find it doesn't happen if I get out of the car and go inside. ;-)

 

car key gnomes

 

Mine was doing a "knocking noise" every time I started driving until I found my son's hot-wheels mini cooper at the rear cupholder