Ok, I have a 96 Ram 4WD 5.9 with 200,000k miles. So I have an strange noise from the passenger side, sounds like upper valve train. It's ahard to explain a noise but you can hear it at idle, it will get louder with engine speed and then blends into the noise at higher RPM's. It's somewhat metalic and somewhat squeak and somewhat an exhaust leak. Mix those together and that's the best I can describe it. I first thought it might be a rocker not getting oil and it was a rocker fulcrum squeaking. So I've pulled the valve cover and they are all getting oil and all going up and down.

I did a quick recording of the noise. It's a bit washed out as I think I got it too close and the other noises may be blowing out the mic. I'll go out later and keep the recorder further away to see if that helps.
http://www.mikesjunk.com/noise.wav



Let me know your thoughts.

 

Timing chains are usually the problem with these motors and it could be that, but i am placing my bets on a spun bearing. Also, you can always take the belt off with the motor cold and start it up briefly (not to long b/c the water pump isnt circulating) and see if the noise disappears. If it disappears its an accessory.