Hissing after shutdown

[bibendum]

Picked up the M yesterday. Anyone notice a small "hissing" sound from the engine after shutdown? Not the same as a fan spinning (much quieter), was wondering if maybe some small circulation to make sure the turbos cool down properly?

[jst2878]

waste gate depleting the last amount of compression? Listen to it while someone shuts your m off.

[///MB]

I think I have it too and I also think it's some kind of turbo pressure being released.

[bibendum]

I was thinking that it might be some pump circulating fluid to keep the turbos cool after shutdown. I have heard stories of turbos overheating, etc. It stops after a while so I'm not super-concerned about it.