What’s the little rattle when you shut off the engine?

[325e '87]

It’s just the quick rat-t-t-t that lasts about a half second from engine.

Also, I got a working 6 button obc for my sons car and the lights come on, the 12:00 just flashes very briefly at maybe a 5 second interval. It gets signal but only for less than a second then it goes away and blips back on in a regular interval. I have no idea where to even start....

[jeffnhiscars]

It could be whats called "dieseling" caused by carbon deposits in the combustion chamber that get hot enough to ignite residual fuel vapors after the ignition is off

[superj]

I think his is more about the actual rattle because I think this was asked on another forum also. I know what he is talking about but I don't know what causes it other then I know the trans has a little rattle from something.