Heavy metallic knocking sound from Engine
Senior Member
Joined: Jul 2019
Posts: 488
Likes: 122
C63 Vert
i’ve seen many of these cars even tuned at 100k miles. Some over 185k miles. I do think there is likely a limit but i’d guess about 200k miles.
on facebook.com/facebook/groups/tunedmercedes there is a discussion. B. @ eurocharged boston suggested it was due to the turbo manifold design and heat with exhaust. He did not think fuel trim affected it.
He mentioned towing or long periods of hard work. Like pulls up a mountain, 1 mile pull etc. is what he thought caused it.
madness motorsports with the build the most powerful cls 550 thread got fed up with the manifold and turbo placement and did new ones iirc.
Last edited by cls5504matic; Apr 5, 2022 at 09:59 AM.
Senior Member
Joined: Oct 2011
Posts: 399
Likes: 14
From: Chicago, Illinois
2008 S63
Im having the same problem with a 2013 ML63, Lower end tick/knock that appears when hot. No loss of power, check engine light or misfires. Have not borescoped it but recent oil change showed no evidence of metal. Is there cases where this issue was caused by anything other than the worse case scenario? Could an exhaust leak or spark plug cause this? Any success stories out there? Also is there a way to swap out the piston/rod before it becomes a total disaster for the cylinder wall? Also shouldn't a knock sensor have gone off by now?
Last edited by Zerocarpileup; Aug 5, 2022 at 11:12 PM.
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Joined: Jan 2013
Posts: 19
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I just bought a silent running 2015 CLS500 with 57,000 miles here in sunny Australia, I know this post is from a long time ago but this issue worries me too.
Do you really think I have nothing to worry about too? If so what changes to the bore/piston relationship did mercedes if any do on the later cars?
I had a 2016 GM LS3 in a Holden Caprice - that thing had piston slap at 40,000 miles when cold which would go away at operating temperature...
thanks
Do you really think I have nothing to worry about too? If so what changes to the bore/piston relationship did mercedes if any do on the later cars?
I had a 2016 GM LS3 in a Holden Caprice - that thing had piston slap at 40,000 miles when cold which would go away at operating temperature...
thanks
Last edited by RA053023; Jan 17, 2023 at 09:08 AM.
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