Engine Knock during startup
Thread Starter
Junior Member
Joined: Feb 2011
Posts: 15
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2008 c300 4matic sport
Engine Knock during startup
Hello,
I have a c300 with 18K miles and have noticed a knock for 2-3 seconds on start-up. It is pretty noticeable and goes away after 2-3 seconds. I'm taking it back to dealer on Thurs. morning. Service advisor said he has never heard of this problem before. Anyone have this problem.
Thanks,
Miguel
I have a c300 with 18K miles and have noticed a knock for 2-3 seconds on start-up. It is pretty noticeable and goes away after 2-3 seconds. I'm taking it back to dealer on Thurs. morning. Service advisor said he has never heard of this problem before. Anyone have this problem.
Thanks,
Miguel
Super Moderator
Joined: Jun 2008
Posts: 19,942
Likes: 192
From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Causes of startup noise in Benz engines (apart from at oil drain)
- Bearing noise (mainly small end) clearance - requires repair
- Piston slap due to ultra short skirt pistons - fine if slight and stops at operating temperature. Benz metallugy maintains fairly consistent piston to bore clearance with temperature change unlike engines with iron blocks or liners.
- Timing chain slap prior to oil pressure reaching max. - Hydraulic tensioners require repair.
- Camshaft adjuster rattle - require deburring or replacement.
Good luck!
- Bearing noise (mainly small end) clearance - requires repair
- Piston slap due to ultra short skirt pistons - fine if slight and stops at operating temperature. Benz metallugy maintains fairly consistent piston to bore clearance with temperature change unlike engines with iron blocks or liners.
- Timing chain slap prior to oil pressure reaching max. - Hydraulic tensioners require repair.
- Camshaft adjuster rattle - require deburring or replacement.
Good luck!
MBWorld Fanatic!
Joined: Oct 2010
Posts: 1,128
Likes: 19
From: Acapulco Mexico
2010 C300 Sport
This subject has for a long time been the subject of many threads in the W204 forum. Suggested is first searching the forum for the answers before initiating new threads, which are redundant and confusing.
https://mbworld.org/forums/c-class-w...ine-noise.html
https://mbworld.org/forums/c-class-w...ine-noise.html
