What is that ticking sound engines make after they turn off?

What is that ticking sound engines make after they turn off?
After every time I turn my car off I always hear that ticking sound coming from the engine, almost sounds like tiny pebbles dropping onto a metal pan. I have always wondered what it was that was making that sound. Does anyone know or have an idea?


Answers:

Uncle Jed:  Its the different metals of the engine and exhaust cooling off.................md
2010-07-29 17:00:51
dj:  the engine cooling down
2010-07-29 17:00:54
No Picture:  metal expands when heated, then as it cools it actually is moving a wee bit against other metal
2010-07-29 17:03:06
idontgivafork:  some call it heat soak, others call it heatsink.if its the first time i hear it i usually call it a leaking head gasket lmao.
2010-07-29 17:15:38