2016 Peugeot 2008 clicking sound - any ideas?

[Johns23]

Hello

I have a Peugeot 2008 (2016) GT Line HDi blue 1.6 diesel - I was checking the coolant level after a drive and heard the sound that is audible at the start and end of my video. It lasts for a few minutes at a slower interval as it goes on. There are quieter similar sounds coming from all over the engine and fuse box (one can also be heard towards the end of the vid but not concerned about these but this one I now notice with the bonnet down) it’s also not the usual popping of metal as the exhaust etc cools down. I only hear this after a drive, not after idling.

Any idea what it is? Location appears to be near the air filter perhaps??

Thanks in advance.

https://youtube.com/shorts/3tbXdGJKQ_k?feature=sha...

[P2KKA]

I worked at Peugeot from '19 to '22 and its not something i recall coming across. Could still be expansion/contraction. The 1.6 hdi is a pretty good engine, just let down by emissions equipment in most cases (leaky urea injector leading to failed cat pipe, urea tank pumps, NOx sensors...) If i was to pick between the hdi and the 1.2 or 1.6 petrol it would always be the hdi.

[Johns23]

Thanks for the reply. This car already had the nox sensor replaced so hoping that doesn’t rear up again.

[GreenV8S]

I don't know that engine, but the noise sounds very mechanical.

Hard to tell whether it's being caused by thermal expansion/contraction, or an actuator. Does it have a throttle, variable geometry vanes or EGR valve?

If you can provoke similar noises by tapping / pushing on components while it's happening that might give a clue where it's coming from. A mechanic's stethoscope can also be very useful to locate mechanical noises like this.