Cylinder damage – Possible Damage from OM642 Timing Chain Guide Fragmentatio
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From: Georgia, USA
2012 Mercedes E350 Bluetec
Cylinder damage – Possible Damage from OM642 Timing Chain Guide Fragmentatio
Hi everyone,
I’m reaching out to see if anyone has experienced something similar with their OM642 engine. My 2012 E350 BlueTec (~210k miles) has developed significant oil consumption, and I suspect it may be related to timing chain guide failure and fragmentation inside the engine.
Here’s the full story:
Vehicle History & Context:
Given the timing chain/tensioner/guide issues and the fact that chain guides fragmented inside the engine. I suspect internal engine damage to Cylinders 5 and 6 may have been caused by chain fragments and contaminated oil.
Questions / Looking For:
I’m reaching out to see if anyone has experienced something similar with their OM642 engine. My 2012 E350 BlueTec (~210k miles) has developed significant oil consumption, and I suspect it may be related to timing chain guide failure and fragmentation inside the engine.
Here’s the full story:
Vehicle History & Context:
- 2012 E350 BlueTec, OM642 diesel, ~210K miles
- Vehicle received Diesel Emission Modification on 10/07/2022
- Timing chain work was covered by Diesel Emission extended warranty October 2023.
- During timing chain repair, the timing chain tensioner was found to be bad, which caused the chain to slap and chain was stretched.
- The timing chain guides fragmented inside the engine, dealer dropped the oil pan to in attempt to retrieve broken fragments. I am not sure how long the guides were fragmented and loose in the engine.
- Soon after timing chain work was done, I started getting warning on the dashboard for low oil. This started happening at about every 700 miles 1 quart was consumed.
- 8/2025 the car is consuming 1 quart every 100 miles and DPF is clogged car is in limp mode.
- I pulled the glow plugs and found that Cylinders 5 & 6 were saturated with oil see image
- Dealer originally suggested oil consumption to be “normal for older engines,” but root cause diagnosis would be expensive so I did not do it.
Given the timing chain/tensioner/guide issues and the fact that chain guides fragmented inside the engine. I suspect internal engine damage to Cylinders 5 and 6 may have been caused by chain fragments and contaminated oil.
Questions / Looking For:
- Has anyone else experienced cylinders damage and oil consumption after timing chain and guide failure and fragments inside the OM642?
- Any advice on confirming the root cause without full engine disassembly?
- I am thinking of making a claim with Mercedes of NA for this under diesel emission extended warranty?
Last edited by Bosko Kukucka; Sep 2, 2025 at 10:18 PM.
Out Of Control!!
Joined: Apr 2019
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From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
If you want to increase the odds of your new claim being successful you should work with the same local MB specialist that addressed your past concerns.
Can you get a "relative compression test" ? This will quickly prove compression loss.
Can you get a "relative compression test" ? This will quickly prove compression loss.
