What's the realistic probability of head bolt failure?
Thread Starter
MBWorld Fanatic!
Joined: Jun 2009
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From: Atlanta Metro
Current: C217 V12TT AMG Previously: C55 AMG, SL65 AMG
What's the realistic probability of head bolt failure?
Has anyone really come across a head bolt failure on these 63's? I'm not sure if the 507 hp engine was different than the regular C63's that had issues?
Super Member
Joined: Dec 2009
Posts: 748
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From: Dhahran, KSA
2020 E 300 Coupe and 2019 GLS 400
The C63 507 Has the updated head bolts, and all M156 engines produced post mid-2011. The engine serial number is the way to verify.
I have only seen a handful of incidents, all of them were reported by Mercedes forums members. This issue affects engines up to serial # 60658. Let us say that only 5% of these engines would suffer the failure during operational lifetime, this translates into 3033 engine hydro locking or blowing-up (worst case scenario). If that was the case, MB/AMG would've done something about it (Like the W211 fuel tank recall, or the M272 timing warranty extension).
All in all, the chances of it occurring are slim, but if it happens, then the owner is out of luck.
I have only seen a handful of incidents, all of them were reported by Mercedes forums members. This issue affects engines up to serial # 60658. Let us say that only 5% of these engines would suffer the failure during operational lifetime, this translates into 3033 engine hydro locking or blowing-up (worst case scenario). If that was the case, MB/AMG would've done something about it (Like the W211 fuel tank recall, or the M272 timing warranty extension).
All in all, the chances of it occurring are slim, but if it happens, then the owner is out of luck.
