The chain itself may be fine but the tensioner sounds like it is the cause of the noise. That's an easy fix. The plastic guide rails however should be changed about every 10 years as they deteriorate more with time than miles. If you are unsure about the last time they were replaced then they should probably be considered soon. For that you would need to break open the chain though so replacement is only another $100 or so at that point to roll in a brand new one.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz