When I turn the car off...

[hawaiiw116]

Aloha All,
When I turn the 450 sel off it makes a funny noise for about a second.  I kind of rattles... then clunks off.  Is this normal?

[Big_Richard]

Aloha All,
When I turn the 450 sel off it makes a funny noise for about a second.  I kind of rattles... then clunks off.  Is this normal?

Could be run on/dieseling, ie glowing hot carbon deposits that ignite residual fuel after the ignition system has been deactivated and allows the engine to keep running for a short while.

Could also be signs of a concerning timing chain situation about to arise. Perhaps a recording is in order.

[Papalangi]

In my case, it was due to ignition timing.

http://forum.w116.org/mechanicals/of-vacuum-and-timing/ explains how I adjusted my timing and it has not dieseled since.

Michael

[s class]

Slight running on can also be caused by vacuum leaks in the intake system.