So you think your timing chain rattles?
 

Vehicle : W202, Engine : 605 5cyl diesel 190,000 mls
only owned this car for 2 months. when starting from cold it sounded very rattly like timing chain worn. As it warmed up, it quietened down. After 2minutes it was OK. I finally tracked down the noise to the aux belt tensioner damper, the small hydraulic strut about 6ins long. Strange that it went quiet after 2mins & it did really sound like chain. In fact the hydraulic part was OK, it was the metal eye bonded into rubber that had worn and was loose in the rubber. I suppose I could have made a new bush for it but the complete part only cost £15 from Eurocarparts, in Glasgow. The Moral of this story, dont jump to conclusions about timing chain problems

don't be suprised if the new rubber bushing comes loose again.
the shock is a weak design and a common failure part.
1 per year is common.