Timing chain tensioner works like a hydraulic litter/follower.

It's filled with oil under pressure to expand. As they age the gaps between the piston/cylinder get bigger and the same amount of oil pressure nets less force on the chain or the tiny paths oil takes gets blocked reducing the internal pressure. Same net result.

I've worked with a few people where it was obvious the chain was rattling because you could hear it in start similar to my M54 which has lifter tick every cold start while they are pumped up. I can actually tell how low my oil is by counting the seconds until lifter tick fades.

If the chain sound goes away after oil pressure builds it's almost certainly weak tensioner.

The knock off tensioners can not be trusted and I would replace tensioners on certain engines proactively. Eg on m62tu change before 120000 miles and every 50k after that.

The sound in the video definitely sounds like a loose chain and if were my engine I would park the car until my OEM tensioner with new crush washer arrived.

If the brand/age is unknown it should be changed anyhow. If the sound is something else at least you can have some peace of mind about the chain not self destruct

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)