Last week my cat started making a fairly loud rattling noise that seems to be coming from the front of the engine. Using the ever handy pipe to ear method I determined the loudest point is behind the water pump and below the intake. Sounds like a rattle clatter, think of a marble in a can. Maybe two marbles.
Heres the part I find odd, the sound is loudest at warm idle. Cold idle there is no sound. Warm idle is loud, but quiets down if given gas. Quiets to where you can barely hear it, alot of it could be hard to hear due to my LTs and TDs though. Car seems to run fine, even at WOT.

I have pulled all the push rods and none are bent, rockers all have their bearings in place. I did notice that on a few of the valve springs are loose and some are tight. Loose meaning I could move the spring around under the top cap easily, doesnt go under the cupped part but probably would if effort was given. Others I couldnt really move at all. Also noticed on the loose ones what looked like rocker to spring contact, fresh metal on both rocker and spring cap. What does this mean?

What should I be looking at?

 

Umm, you shouldnt be able to move the valve spring at all if its installed correctly. You can move the valvespring around while its installed with the locks/retainers and everything?

 

yes I can. All I did was remove the valve covers and the rockers. Most springs will move around quite bit.

 

I dont think thats right. I cant imagine a spring being able to move around once installed