DV5 rattle

[Superflan]

Id like to help a friend with a recently appeared engine rattle. It's a DV5RCF engine (1.5 BlueHDi 100) in a Citroën Berlingo, first put on the road on 2021-08-30. It has 95000km and started developing a rattle linked to engine speed, not depending on load/torque direction. That engine family is known for timing chain failure (there's a driving belt but between the two camshafts there's a chain). Here's the service history regarding oil changes:
2022-03-28 18321km oil change with Total Ineo HTC 5W30
2022-11-10 36714km oil change with Total Ineo HTC 5W30
2023-08-21 56211km oil change with Total Ineo HTC 5W30
2025-06-28 90203km oil change with Elf R-Tech Elite 5W30 (RN17)
Regarding the spaced out intervals (local service plan says 15000km or 1 year whichever comes first), I think it could be something blocked by excessive soot, or might be the timing chain scrapping on something or on the worn out tensioner pad. Since the dealer will refuse to warranty the timing chain issues anyway due to the intervals stretched more than +3000km/+3months, would it be worth it to do an engine flush and then use a different oil in attempt to free a stuck VVT (the rattle sounds like an unpressurized VVT issue rather than a scraping chain issue), or should I open the head cover anyway ?

The rattle, in a 4/8 pattern, doesn’t sound like a chain rattle to me, more like a vvt/stuck lifters. Here’s on cold:



And on hot, with a faint knock in background but I could only hear it on the video:



Any insight appreciated on what could be the chances of a chain noise or anything else

TIA

 

[Bailes1992]

Yeah, that's the chain alright! PSA/Ford used a 7mm chain and later revised it to an 8mm chain, I suspect as the 7mm chain was failing so often. Replace the sprockets as they wear with the chain and replace the chain with the 8mm version.

 

[Superflan]

Yeah, that's the chain alright! PSA/Ford used a 7mm chain and later revised it to an 8mm chain, I suspect as the 7mm chain was failing so often. Replace the sprockets as they wear with the chain and replace the chain with the 8mm version.

The 8mm chain conversion includes replacing the tensioner, cover and… camshafts, as the sprockets are part of them. Therefore, you can still buy 7mm chains and tensioners to fix for cheap.

My concern here is, is it really a chain wear rattle or a chance that it is a blocked oil way near vvt or tappets ?