M112 engine has a manufacturing defect, or what this is
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Junior Member
Joined: Sep 2010
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From: Southern Finland
C320 W201 W202
M112 engine has a manufacturing defect, or what this is
Question thread.
M112 engine has a manufacturing defect, or what is this ....have you got same problem in M112 engine?
I have the same symptoms as a link M112.
I'm told my problem this forum thread C320 Knock Knock Knock...and peachparts show thread is 100% same problem as my.
Is this connecting rod, main bearing, piston slap or normal noise ? Can you tell me who know that?
That is very strange ----> Why do so many of the car and the same problem,
SAME PROBLEM THIS LINK http://www.peachparts.com/shopforum/.../t-230876.htmland the other two cars in here what I know, but my noise is very loud, some car it is quiet
and link full version http://www.peachparts.com/shopforum/...d.php?t=230876
(I believe almost everyone M112 V6 engine can hear this sound, one car is a quiet voice and a second car a louder voice. Loudness variation) Am I right?
M112 engine has a manufacturing defect, or what is this ....have you got same problem in M112 engine?
I have the same symptoms as a link M112.
I'm told my problem this forum thread C320 Knock Knock Knock...and peachparts show thread is 100% same problem as my.
Is this connecting rod, main bearing, piston slap or normal noise ? Can you tell me who know that?
That is very strange ----> Why do so many of the car and the same problem,
SAME PROBLEM THIS LINK http://www.peachparts.com/shopforum/.../t-230876.htmland the other two cars in here what I know, but my noise is very loud, some car it is quiet
and link full version http://www.peachparts.com/shopforum/...d.php?t=230876
(I believe almost everyone M112 V6 engine can hear this sound, one car is a quiet voice and a second car a louder voice. Loudness variation) Am I right?
Last edited by C320 Make; Sep 23, 2010 at 02:06 PM.
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
These engines run very short skirt pistons - A tiny amount of slap I guess is possible but unusual. I thought I could detect marginal piston slap in my car's engine during break-in at unloaded idle. By 5000Km I could hear nothing so I don't really know what it was. I certainly don't believe that all M112 engines suffer audible piston slap. We have had no complaints on this forum. If damage was being done to the thrust side of the piston it would show immediately in oil sample analysis. We see no such thing.
The guys in the above posted links are confused with cast iron block engines. Piston to bore clearance remains almost constant on the M112 with varying temperature. The coefficient of expansion of materials is very similar.
Thin-wall aluminium, Alusil bore blocks do transmit more noise than iron or iron sleeved blocks.
I will look with interest at what the Helsinki workshop finds.
Apart from piston slap & a small-end bearing knock that we are investigating as likely causes of this noise - I remembered a problem that Benz had a long while back that is worth checking. For a short period they had a problem with gudgeon pins (wrist pins) coming loose in pistons - you should check this.
The M112 engine went through 3 piston redesigns in it's life. What year is your car?
German engines tend to be a little noisier than Japanese ones - Especially Toyota. I find Benz V6 engines pretty quiet considering their moving parts count. I also find Benz hydraulic lifters to be remarkably quiet.
The guys in the above posted links are confused with cast iron block engines. Piston to bore clearance remains almost constant on the M112 with varying temperature. The coefficient of expansion of materials is very similar.
Thin-wall aluminium, Alusil bore blocks do transmit more noise than iron or iron sleeved blocks.
I will look with interest at what the Helsinki workshop finds.
Apart from piston slap & a small-end bearing knock that we are investigating as likely causes of this noise - I remembered a problem that Benz had a long while back that is worth checking. For a short period they had a problem with gudgeon pins (wrist pins) coming loose in pistons - you should check this.
The M112 engine went through 3 piston redesigns in it's life. What year is your car?
German engines tend to be a little noisier than Japanese ones - Especially Toyota. I find Benz V6 engines pretty quiet considering their moving parts count. I also find Benz hydraulic lifters to be remarkably quiet.
Thread Starter
Junior Member
Joined: Sep 2010
Posts: 38
Likes: 0
From: Southern Finland
C320 W201 W202
A little strange thing that a large world, but similar case as the link does not exist on this forum? Listen carefully, I believe that the voice is there. One strong voice in the car, another car audible sound, this sound difference is due to many things.
The problem affects V6 M112
M112 Link Symptoms of a loose cylinder piston or piston pin? Damage to the piston or cylinder? Shame when I can not ask for a link to nickname the Volvo 164 and ray95e320se nickname and what their coaches nickname hookedon210s diagnosis?
Whether they have received additional information
the link is already old and I do not know how they could ask about this matter? Is it the fault survived? Contact?
The problem affects V6 M112
M112 Link Symptoms of a loose cylinder piston or piston pin? Damage to the piston or cylinder? Shame when I can not ask for a link to nickname the Volvo 164 and ray95e320se nickname and what their coaches nickname hookedon210s diagnosis?
Whether they have received additional information
the link is already old and I do not know how they could ask about this matter? Is it the fault survived? Contact?
Last edited by C320 Make; Sep 25, 2010 at 09:51 AM.
