I was driving my 97 to work today, and I heard a clunk sound, not real loud, but I could definately hear it. It was followed by a whining sound, kinda like a power steering pump whine. The sound changes pitch and loudness with engine speed. There is also a slight vibration now. I drove on to work, about 5-8 miles at 65 or so, and the noise never stopped or got worse. It seems to be from the lower end of the engine, but its hard to tell. Im fairly confident that its not an accessory, I checked them all. I cycled the a/c amd the noise didnt change, and it doesnt seem to change with steering input either, and steering seems as easy as it was. I listened to the alt, and it doesnt seem to be from there. Any ideas? Could it be the tensioner? The bolt sticking through the cover seems a little crooked, but I couldnt move it.

 

it could be the tensioner but if there was a clunk first then I'm not sure. Hopefully the belt isnt rubbing anywhere, maybe pull the valve cover to check it out.

Oh and since you said it vibrates more, maybe the balancer belt or one of the pulleys/tensioner broke

Whining is most definitely a belt noise though