New sounds..

It's hard to say from that brief description, but there are whirring and pumping sounds from the engine compartment right after shutdown. The most common is the coolant transfer pump moving hot coolant to the thermos bottle (North American models only). It doesn't do it every time, only when certain conditions are met, but it does do it commonly.

Tom

 

Mine does this all the time and it's only 2 months old, my previous '08 did it as well. I assume it's normal operation.

 

I agree that it sounds like the coolant transfer pump. (There are some brake system exercises that go on too, but that's a few minutes after you turn the car off.)

I just had my coolant transfer pump replaced. Mine was noticeable but sounded healthy when the car was new. After about the first year, it started getting louder and very grindy and unhappy. The replacement is quieter than the original, to the point that you wouldn't notice it if you weren't paying attention.

My hunch is that your pump is just getting old and ugly sounding. Even if that pump does eventually die, it's not make the car leave you stranded- the worst it will do is turn on a warning light. The whole coolant heat storage system is sort of an optional thing they did for emission control.