2009 Smart. On start up I get a strange noise. Zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz. It doesn't change with rpm's. Changed tension pulley, removed A/C belt. It is not the alternator. It lasts about 20 seconds and then powers down slowly and goes away. After it stops it will not come back unless the car is completely cooled down. This is a loud noise that definitely comes from the passenger side of the motor. I'm stumped.