Knocking from deep down?

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Yogi bear

Member
Joined
Dec 9, 2012
Messages
43
Location
Lincoln
Car
W203 C180 Kompressor Coupe
C180k engine from a W203....on idol it's making some knocking noises from what sounds like deep down somewhere!

Any ideas or feedback is appreciated.
 
Hi. I've had similar problem with noises coming from engine, so I've been doing some research. Is it just knocking at idle?

Get someone to rev the car @ 2000, if the knocking sound creep back in after a few seconds it could be a bearing.
 
ive got same with my c200k 2009 w204 dealer couldnt diagnose and said noisy egr valve and normal
 
ive got same with my c200k 2009 w204 dealer couldnt diagnose and said noisy egr valve and normal

Noisy egr valve? This won't cause knocking!
 
If an engine knocks there is something wrong with it. If you continue to drive and the knock gets worse there will soon be a lot more wrong with it, and it may go past the point of economic repair. Get some advice, quickly, or you may be towed to your next destination.
 
Nothing like stating the obvious there!

I'm assuming it could be bottom end or a crank bearing
 
Hi
could be big-ends going, main bearings usually rumble rather than knock
I would take a 'listening stick' to it and see if you can localise the noise, it can be misleading as to where the noise is actually coming from.
If it is big-ends you would probably get some loss of oil pressure and or mpg/performance
Is it continuous at idle, hot or cold, worse uphill or anything like that?
cheers
 
Yogi bear said:
C180k engine from a W203....on idol it's making some knocking noises from what sounds like deep down somewhere!

Any ideas or feedback is appreciated.

What engine is it? A 111 or a 271? But have never known either to suffer with bottom end issues.
 
Hi
could be big-ends going, main bearings usually rumble rather than knock
I would take a 'listening stick' to it and see if you can localise the noise, it can be misleading as to where the noise is actually coming from.
If it is big-ends you would probably get some loss of oil pressure and or mpg/performance
Is it continuous at idle, hot or cold, worse uphill or anything like that?
cheers

The strange thing is it runs perfect, comes up to temp and stays there, mpg still good, pulls very well! Probably nothing's just me being really ****!
 
Nothing like stating the obvious there!

I'm assuming it could be bottom end or a crank bearing

I know. But the inference that could be drawn from the OP was that a car with a knock was still being driven, with the source of the knock unrecognised. Some knocks you can take note of, some you must take action about and PDQ, or you will find yourself with a ventilated crankcase.
If you can't tell the difference between a loose bearing and a worn cam follower you could be in for a lot of expense.
The engine in my Bentley rattled for years, but when the water started to mix with the oil it was immediately taken off the road and stripped down. Even so the crankshaft was in good condition and the main and bigend bearings still serviceable, the noise emanating from the valve gear, and piston slap caused by two missing top rings.
 
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Listening out for strange noises is a pretty good way to avoid minor issues turning into expensive problems...

Only other thing that springs to mind is engine mounts, the engine tends to jump around a bit, especially on start up, and can 'clonk' about...ask me how I know...
 

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