2002 Saturn L300 chatter in top of motor

One way you can locate exactly where the noise is coming from is to take a long screw driver, or anything else long thin and solid, place it on something solid you want to listen to and put your ear up to the other end, by process of elimination you can find where the noise is the loudest. I am not familiar with what engine is in your car, but part or all of the valve train is up there, so it could be excessive clearence in the rockers cam followers push rods etc. This can be caused by wear or by something sticking. Both may be helped by a fresh oil change and or running an oil additive through it. It may also be as simple as something that loosened up and is vibrating with the engine.