What makes you think it's a timing chain tensioner?
What kind of noise?
When does it do it?
How long does the noise last?

C220's are fairly bulletproof and I have not seen any needing a chain or tensioner until they rattle or break a rail around 150k.

If your engine uses a belt shock near the serpentine belt tensioner, that may be your culprit. Those tend to have a weak rubber bushing that fails and they rattle and buzz.

DR.D