I've recently upgraded my 2013 MS to a 2016 model, and noticed that the new car always seems to have a hum while parked in the garage. Doing some searching revealed that it's expected that there would be some humming due to coolant circulation and such, but I don't think it should be lasting this long, should it? For example I've been keeping an eye on the car for the past 7 hours now, and the electric hum has been present the entire time. Does anyone else experience this with their MS?