Noisy problem [video include]

[Stryke911]

Hi ! So ... the pitched noise is like an angry cricket, really noisy, inside and outside the car, occuring sometimes between 680-2800 rpm (and never when > 3000 rpm). This last one is totally independent from the running engine (like : grik... griiiik grik... griiiiiiiik.... grik... grik............ grik..... stop during few seconds, and continue).

My IMS seems good, because I didn't find any plastic or metal piece captured inside the oil filter. I don't have any fault code with my Durametric (V3). I recently removed the accessory belt and the noise was audible. I also checked the clutch, my spark plug... everything is ok. My car works like a normal Porsche, but with this noise...

How can I separate the provenance of the noise between the ...
...Chain tensioner ?
...Gearbox ?
...Secondary air pump ?
...Separator air/oil ?
...Worn chain guide ?

I think that it's a real big challenge for every Porschist....