My car is making a terrible noise. It started this morning when I turned the car on. The best I can explain it is a loud roar or a rumblingcoming from under the hood. It roars/rumbles when at a stop sign or stop light, when I turn left or right, and when the car is in any gear other than Park or Nuetral. Any idea what this might be? Power steering pump? Low power steering fluid? Engine Fan? Please help!

1998 C230
36,000 miles