The coolant transfer pump has gotten noisy. It happens frequently when starting and almost every time after shutting down. But so far it has never happened when I take the car in for service!
It can get pretty noisy when it's cold. I thought mine was bad or going bad, but in warm weather and after the car's warmed up it usually isn't that loud. On frigid mornings it sounds like you're waking the dead. They can go bad and at least one or two people have had to have the pump replaced. If it continues to get worse or sounds bad even when it's not cold out your service tech can check it.
Mine was so noisy last summer, it sent a lady backing up slowly, constantly staring at my car as we sat in front of a drive in burger joint. From the look on her face, you would think the car was about to blow up!
