Slight knocking noise on cold start.
Thread Starter
Junior Member
Joined: Oct 2011
Posts: 34
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From: Richmond, Tx
2015 C63s Sedan, 2013 Ford SVT Raptor
Slight knocking noise on cold start.
I saw someone else ask this in the S-Class (W221) forum, and it reminded me that I too have heard this and thought I'd ask here..
On a cold start I hear what sounds like a faint knocking sound for about 1-2 seconds and then it goes away.. Is this normal? The car has roughly 50k on it.
2009 C300 Sport 3.0 V6
On a cold start I hear what sounds like a faint knocking sound for about 1-2 seconds and then it goes away.. Is this normal? The car has roughly 50k on it.
2009 C300 Sport 3.0 V6
Last edited by Whitey92Lx; Oct 19, 2011 at 01:47 PM.
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Joined: Jun 2008
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Two causes of very slight noise on cold startup that I would consider normal. A very slight timing chain or cam adjustor rattle until full oil pressure is achieved. Chain tensioners are hydraulic. Very slight piston slap until full oil circulation & warming closes piston to bore clearance. These engines run very short skirt pistons.
Neither of these is an issue unless they become prolonged or permanent.
Neither of these is an issue unless they become prolonged or permanent.
