[gman]

I hear every time I turn off the car? Sounds like an antenna retracting, but it's got to be something with the engine??? I'm sure it's normal but I'm too lazy to look figure out what it is.

 

[jamarimutt]

It's an electric pump filling up a stainless steel thermos with hot coolant.

 

[BIF]

Yup, that's what it is. If you hang out near your Prius after you shut it off, you'll hear other noises later on. I don't know what those are, but they happen about 3 to 5 minutes after you shut it off, and they too, appear to be normal.