I know its always hard when you are not actually there to diagnose a noise from a car, but here I have a video of a extreme metallic rattling sound, kind of like a marble in a soda can. It is incredibly loud as always on startup but it also will make the rattling noise while revving the engine throughout like 2000-3000 rpm while driving or still.
I have done a lot of research on this topic and a lot of work on this car to no avail of this sound going away, I'm sure of it not being any vital engine components as its been making the noise for almost 50,000 miles now.
The work I have done is a whole new clutch kit (pressure plate, disc, pilot bearing, throw-out bearing, and fork), the full timing kit (new chain, guides, tensioners, cam gear, crank sprocket), I even tore into the valve cover and investigated all the roller rockers as well as replacing the hydraulic lifters which did not fix it.
The only things I have not tried yet are exhaust manifold leak which I'm not sure how that could be making that noise. Or perhaps maybe it could be the oil pump related considering I did not replace it after the timing guides went out.
I also did investigating into the transmission inspection plate being the vibration and that came up with no obvious vibration.
Thanks for any help

 

Sounds Like a Valve Lifter to Me. Cam Lobe May Be Flat. I guess you Have Investigated that Area But That is What is Sounds Like. My Links May not Help Your Situation but May Help Others to Track Down if They have Issue. I have Had Exhaust Leaks in the Past at the Manifold on a 5.4L 2v and Did Not Sound Like Your Issue. May Gleen Something By Watching all These.

Found This!

You Tube

And This

You Tube

And Finally

You Tube

Good Luck!

Any Other Idea's Out There Chime in!

Kc

 

My advice is to get mechanic's stethoscope or a length of tube. Even a looong screwdriver or even a coat hanger bent 'straight' or whatever angle you need might can do it. It may not be coming from where you think. You put one end of the 'device' near/on some component and listen to the other end. It will amplify the sound when you are nearest it. All but the tube will require you to be touching components, but the tube will not, just close, and may in fact be the better idea depending on where that sound it coming from.

And while I agree with Kevin up there in things it could be, the truth is that it also sounds like some rattling shield, perhaps that one for the clutch cable or maybe the catalytic converter shield. Had an SVO that did this silliness, turned out it was the driveshaft balance/noise weight they had on it was scraping the cat which was crossing over the underside of the car directly under the driveshaft yoke. Took a big dang crowbar and bent the shield that they had on the cat, rattle went away, tada.

I don't think this sound is engine specific, or even car/manufacturer specific. Just a thing that's happening. For what my opinion's worth on that, surely.

Hope that helps, and in any event good dang luck to ya.