Cooling ?

[rgv250ads]

Hi all, just come back from a drive, rather spirited, and when lifting up the bonnet to plug in the battery conditioner I noticed a whining sound coming from this little motor hanging off the coolant reservoir. I assume it's some kind of engine off coolant circulation system, powered by a little 12v pump. For reference it's a 2016 E400. Any info would be appreciated. Adam.

[UltimaCH]

I imagine it must be something like that and sound very useful when you turn off the engine after a spirited drive. Gets a continuing flow of water to cool down and avoiding hot spots in the engine block