Plase help me identify this rattle.

[c.f.169]

I posted this in the small questions thread with no reply.

Please help identifying this rattle. The rattle is very prominent in the exhaust area. Not from the front of the engine. This only happens on cold starts and only lasts for a fraction of a second. If I turn the car off after the first initial start and start it up again the rattle disappears. Does this sound like an exhaust leak. Thanks guys.
*EDIT* This noise started after I did my rear main seal. I had to remove the down pipe/ exhaust to remove the transmission. The Exhaust manifold bolts are all tight, as well as turbo to manifold. I'm stumped, but its definitely the exhaust side. The heat shields are removed to eliminate the possibilities.
bOGoarxnXmo
I changed the ehaust manifold gasket and the noise is still present. Anyone? Does this sound more like wastegate chatter, or a sticky valve or exhaust leak?
Here is another video from today. 2tlcJ7VrJEk

Hopefully I can figure out what this is. Thanks in advance!

[c.f.169]

Do these symptoms sound similar to a timing chain tensioner?

[BoostWanted]

Timing chain tensioner would be persistent and not go away after a few seconds. Same with the timing chain guides. It sounds like it but I think if it was timing, the sound would not go away.

[c.f.169]

Thanks for the reply. From my understanding with the timing chain tensioner it's related to oil pressure. It makes sence that it would do this on cold start up as oil pressure is low. And after the first intial start the oil pressure is built up and increases tension on the chain. From my research, timing chain guides, when they go they will make a constant noise. I just ordered a new tensioner and gasket from frsport. Really hoping I figure this out.

[c.f.169]

Bump. Any other suggestions before my timing chain tensioner gets here? One guy said it may be the turbo... Its a brand new gt2560r with 125km on it. I'm all ears and any help is good help. Thanks