I have this used car for the past 5 months, has 189,000kms on the clock and it has absolutely no power and makes this metallic chatter on acceleration , noisier when cold and the exhaust sounds too loud too. Its a 1994 C180 model 4 cyl 1779cc engine. Books don't show any serious engine or trans work done to it. Wonder if this is "normal" for such a low power engine pulling such a heavy weight or its time for an overhaul??? Running on 3 cyls or needs new exhaust system or the auto trans has had its day or what? I am appealing to the techs if you can tell me whats wrong. As far as I am aware of most cars, they usually purr away smoothly even when cold, but this one makes this irritating metallic chatter like "clack, clack, clack,clack for as long as I have my foot on the accelerator while getting away from stationary position like red lights or parked or uphill, otherwise its normal. Do I need to send for computer diagnosis or just rely on the tech's ears??? Please help soon, thanks.

The engine is 1799cc or 1800 and not 1779cc, I'm sorry for the error.

Could this be detonation? Also called pinking, pinging or pre-ignition.

This is normally caused by poor fuel, or carbon buildup in the combustion chambers. I would have thought that the engine management system would accomodate the poor fuel with some kind of knock sensor. I'm sure the techs know lots more about this than me.

Detonation is bad for your engine, it can burn out valves. I would get someone experienced to check this out.

Clattering when cold is usually the hydraulic tappets, but this would go away or reduce when warm.

Sluggish performance is a subjective thing. Have you compared your car with other 180s?

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Cheers, Neil

Thanks Neil, the fuel is Shell, Mobil or any of the other well known brands and its premium unleaded fuel. So the quality I don't think is the issue here. It is probably more a failing part like the tappets or valves or somebody said its the Cat. which costs A$1000 to replace! I've jacked the car up and the cat. looks new and recently replaced by previous owner. The muffler may have a small leak which I cannot see, but a tech said so. The noise comes around 2000rpm if this helps and goes at higher revs. I have compared with other C180s and C200s and they also clatter at this rev, but they do not make this noise when moving, only on stationary revving. Mine makes the most noise on acceleration from lights and slow crawls. Its like its complaining that its got not enough power to push the car along! Could be pinging? Or is it the pistons worn out or what? Is a total engine overhaul necessary? Don't someone out there tell me its "designed" to sound like that or they all make this sound!

Sometimes my auto operates well, sometimes it is a bugger like when its cold starting. The front suspension feels like its got no rubber. Feel the bumps a lot when road is rough. Thought the Mercs go like the Lexus cars floating on a "cloud"!!!

If you've had a mechanic look at this then he will have identified detonation if that's what it was.

I would have expected him to know valve gear noise too.

My 190E made an awful racket when warm, but not when cold or really hot. This turned out to be a crack in the exhaust manifold. Maybe your noise is related to the exhaust system somehow.

Sorry I can't help more but descriptions of noises just aren't the same as hearing it!

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Cheers, Neil

Thanks again Neil. My car is going to see the doc this Saturday. Hope he can find out what is wrong with it and has a simple and cheap solution. Unfortunately over here, its always an expensive solution and you don't know if it is the correct one too! I find that they always discover something is wrong even if there isn't any and want to replace things. Otherwise they will get you a long list of "failing or failed" parts which are questionable for us people who are not in this repair game.

More opinions and assistance are awaited from other Benz owners and techs, thanks.