strange noise in 97 Passat GLX VR6 wagon

We just bought a 97 GLX VR6 wagon, and I've noticed a strange noise from under the hood after the engine is turned off. It seems to be coming from behind the engine, but it's hard to localize. I know it's not the cooling fan, because this noise remains even after the fan shuts off.

The noise sounds like maybe a fuel pump, because it has that high-pitched kind of sound. It's audible through the hood, but if I raise the hood, it's much more obvious. The sound persists for some time after the engine is turned off, but does go away after a while.

Anyone have any ideas? Is this normal? Thanks.

There is a coolant circulation pump that will run for a few miniutes after the engine is shut down. It is located just above the transmission on the side of the engine just to the rear, where all the coolant hoses converge.

There is a coolant circulation pump that will run for a few miniutes after the engine is shut down. It is located just above the transmission on the side of the engine just to the rear, where all the coolant hoses converge.

Thank you very much for the reply! That sounds about like where the noise comes from.

Thanks again.