1996 Chevy Lumina Noise from engine only when the Air Condi

I have a '96 Chevy Lumina Sedan 3.1L 6cyl. Every time I turn on my Air Conditioner inside my car, I hear a clicking or grinding noise coming from under the hood. As a matter of fact, when I turn up my A/C, the louder the sound becomes. When I turn the A/C back off, the sound becomes more quiet. When I check, it sounds like it is coming from the engine block on the left side near the belts. But I cannot figure it out.