I have an 08 accord exl v6 and i hear the same noise you are talking about. i noticed it when it was cold out but it seems to happen every time i start the engine now. i also hear an electric whine in the engine right after i shut it off. it almost sounds like a pump. not what that it either. if anyone could give me an idea of whats going on that would be great. bought the car with 42K now have 82K and starting to get nervous.