When the temperature drops below or around twenty degrees overnight, my 07 Camry sounds like an electric grinder being used on a piece of steel when I start it up. The problem occurs only when the car has been sitting for a while and it's cold out, but i am pretty sure what ever is making that sound can't be good for the car. It figures my first brand new vehicle has to be a car that i thought was top of the line in it's class, but you know what they say happens when one ASSUMES! The whining sounds decreases as the idle goes down but i always let the car run for a lil bit before I hit the road for fear that the engine will blow up.