it sounds like you have recognized the great timing chain rattle. No matter what you do to it, it will happen again. The problem occurs because the timing chain tentioner check valve loses the pressure trapped in the tentioner. A new tentioner won't do it til it does. It will happen eventually some time. If it happens often the risk of failure increases.

The problem that relates to this is that during the event the chain bangs against the rails put there for such purposes. Unfortunately they built the rails out of plastic that petrifies into something as brittle as glass. This can break the rails and the pieces cause the damage.

You should have the rails integrity verified and if they have turned amber or brown they should be replaced. You probably should replace the tentioner if the rattle happens often even with good rails. And when it happens you are probably are better off just letting the engine run as the return of oil pressure is when the noise go away. To restart the car three times and rattle each time without running long enough for pressure you just magnify the risk of something breaking.

Mostly I wouldn't worry about it, if your history is true.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician