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1999 slk-230
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Discussion Starter #1
hi folks,

long time lurker, first time poster here.. 99 slk-230

have had this rattling noise coming from the engine for quite a while now.. especially when putting it in gear to move from standstill, or coming to a stop.. it goes away when it's in park... there doesn't seem to be any loss of power, leakage, or increase in gas consumption...I asked the adviser at the dealer, but you guys know the drill, gotta cough up that couple hours labour :read: so you can get an answer :mad:

what could the source of the noise be? :help:
 

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1998 SLK 230, 2016 Tesla Model S P90D, 1984 Alfa Spider Veloce, 2008 E320 Bluetec (former)
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I will be as vague as your description: It could be a lot of things. :)
 

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98 red 230 slk
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Thanks for comming out of the bushes into light where we can see you..Info is vital, more is better, Year, milage and oh and most important, color! RED being the most desired... :)
 

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1999 slk-230
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Discussion Starter #7
many thanks for your replies folks..
try the pulley tensioner sometimes makes this noise in low rpm
I think you're on the right track... I had heard this from other fellow slk owner before.. how do you go about that?

Bazzle, you mean the belt tensioner?

cacecef, mine is 99, 230 kompressor, black, with 185,000 km...
had it since new and wife drives it, but not for much longer as she's already in the market for a new clk... prolly get another year out of it before we kiss it good bye :crybaby2:... this little black beauty served us well :(


and panther, no it's nothing like that... I can say it made the noise since 4-5 years already... it's just becoming more noticeable..


many thanks again guys... much appreciated:)
 

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many thanks for your replies folks..

I think you're on the right track... I had heard this from other fellow slk owner before.. how do you go about that?

Bazzle, you mean the belt tensioner?

cacecef, mine is 99, 230 kompressor, black, with 185,000 km...
had it since new and wife drives it, but not for much longer as she's already in the market for a new clk... prolly get another year out of it before we kiss it good bye :crybaby2:... this little black beauty served us well :(


and panther, no it's nothing like that... I can say it made the noise since 4-5 years already... it's just becoming more noticeable..


many thanks again guys... much appreciated:)
Might be time to add some oil.
 

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1998 Mercedes 230 SLK
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351 Posts
my belt tensioner did the same funny thing until replaced. MB mechanic couldn't diagnose it, the guy from the corner gas station did and replaced part for $50 or so.
 

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1999 slk-230
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Discussion Starter #11
my belt tensioner did the same funny thing until replaced. MB mechanic couldn't diagnose it, the guy from the corner gas station did and replaced part for $50 or so.
thanks silberpfeil1234,...

more or less same thing here, the advisor could not tell, or did not want to tell, what the problem could be... how much did the tensioner cost you?
 

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Hello all,

Just saw this post, and I noticed the same EXACT problem since I bought my '98 slk last year. It has gotten progessivly louder over time, but it always has the same symptoms.

During idle, no noise, then as I put it into gear and begin to accelerate, there is a rattling noise from about 0-->10mph. It disapears after a second or two as the car really gets going (above 10mph). Then as I slow to a stop, it rattles again just as I reenter the 10-->0 mph range. It does this at all stops basically, and I never heard it at high speeds.

As a bit of an aside, my cat converter went bad and I thought that was the source of the rattling, but after replacing that, the original rattling from 0-10mph is still there.

Would be very curious to see if that belt tensioner was the problem. Was there any resolution to the original post?

Thanks
 

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1998 Mercedes 230 SLK
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thanks silberpfeil1234,...

more or less same thing here, the advisor could not tell, or did not want to tell, what the problem could be... how much did the tensioner cost you?
About $25.00.
 

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1990 560SEL, 1999 SLK, 2005 BMW 525I
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ENGINE RATTLING UPON STARTING

My '99 230 has an engine rattle upon a cold start. It last last less than a second. Perhaps long enough for oil to reach all engine parts. Car has only 12,400 miles. Any concerns or comments. Thanks
 

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1998 Mercedes 230 SLK
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Hello all,

Just saw this post, and I noticed the same EXACT problem since I bought my '98 slk last year. It has gotten progessivly louder over time, but it always has the same symptoms.

During idle, no noise, then as I put it into gear and begin to accelerate, there is a rattling noise from about 0-->10mph. It disapears after a second or two as the car really gets going (above 10mph). Then as I slow to a stop, it rattles again just as I reenter the 10-->0 mph range. It does this at all stops basically, and I never heard it at high speeds.

As a bit of an aside, my cat converter went bad and I thought that was the source of the rattling, but after replacing that, the original rattling from 0-10mph is still there.

Would be very curious to see if that belt tensioner was the problem. Was there any resolution to the original post?

Thanks
Actually, the worn-out idler pulley was loudest when idling, and the clatter subsided once I took off so your noise issue may come from other sources e.g., as suggested by Bazzle in the other post. Still with the engine: The 230K has a chain-operated variable intake cam; the chain tensioner could be worn. Some mechanics still know how to use a stethoscope to trace engine noise (that's how my mechanic traced it to the idler pulley).
Otherwise:
Suspension: Is the rattle provoked by uneven road surface? That could point to loose /worn front suspension parts e.g., bushings.
Exhaust: Also inspect the heat shield next to the exhaust header and pull it away if there seems to be insufficient clearance. Have a mechanic check for sufficient clearance of the exhaust system front to rear.
Engine mounts: Signs of engine mount wear (rubbing on adjacent hoses, firewall etc) are probably harder to detect in a longitudinally-mounted engine and you may see the problem only upon disassembly of the engine mounts at which point in time you may change them anyways.

Be prepared for a longer wait time before tracking the culprit. Car noises can be very frustrating as the many hollow parts in a car channel noise from the most unlikely spots to your ear.
 

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...Still with the engine: The 230K has a chain-operated variable intake cam; the chain tensioner could be worn. Some mechanics still know how to use a stethoscope to trace engine noise (that's how my mechanic traced it to the idler pulley).
Otherwise:
Suspension: Is the rattle provoked by uneven road surface? That could point to loose /worn front suspension parts e.g., bushings.
Exhaust: Also inspect the heat shield next to the exhaust header and pull it away if there seems to be insufficient clearance. Have a mechanic check for sufficient clearance of the exhaust system front to rear.
Engine mounts: Signs of engine mount wear (rubbing on adjacent hoses, firewall etc) are probably harder to detect in a longitudinally-mounted engine and you may see the problem only upon disassembly of the engine mounts at which point in time you may change them anyways.

Be prepared for a longer wait time before tracking the culprit. Car noises can be very frustrating as the many hollow parts in a car channel noise from the most unlikely spots to your ear.
Let me clarify the noise a bit, I noticed yesterday, that it actually was rattling at low rpms, not just low speeds. I guess its just less noticable at speed. It seems to concentrate from 0-15rpm and then stops completely above that... Doesn't seem to matter what gear.

When I hit the gas pedal, the car rattles briefly in and disapates after i give it a bit more gas. Again, I reiterate, in PARK, no matter how much I rev the engine (up to 5 even) the engine/mounts/exhaust are all fairly quiet.

Thanks for the thoughts/ideas.
 

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1998 Mercedes 230 SLK
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Have you tried locate the noise with the hood popped open while some else is playing with the gas a bit? At least you'd be able to discern front engine noise (eg pulley, compressor clutch, chain tensioner etc) from noise that might come from exhaust (cat, heat shields etc) parts. Since it is present at idle you can safely exclude suspension; I think engine mounts are unlikely too. If you think this might emanate from the exhaust you'll have to jack up the car to get a good look at cat, brackets, shields etc.
 

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Have you tried locate the noise with the hood popped open while some else is playing with the gas a bit? At least you'd be able to discern front engine noise (eg pulley, compressor clutch, chain tensioner etc) from noise that might come from exhaust (cat, heat shields etc) parts. Since it is present at idle you can safely exclude suspension; I think engine mounts are unlikely too. If you think this might emanate from the exhaust you'll have to jack up the car to get a good look at cat, brackets, shields etc.
Actually, you can throttle the engine by yourself (just pull the throttle cable ;)).

Dont think it is exhaust because doesn't do it in park when reving (also just replaced the cat).

Also, I'm leaning towards the engine bay at this point, but its hard to tell (since you have to be driving)

Also, Just to clarify, it definitly sounds like the rattle is related to some belt reving up (maybe a loose pully is banging around) because the rattling is a fairly consistent frequency (like metal rattlesnake). Just want to distingush that from the rattling of a bad cat converter (which is more like a random object bouncing around).

Because of that, I'm leaning towards something in the engine bay being shaken in rhythm with the acceleration.... so maybe a belt/pully shaking?

What's a compresser clutch?

Thanks
 

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1998 Mercedes 230 SLK
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Actually, you can throttle the engine by yourself (just pull the throttle cable ;)).
....

What's a compresser clutch?

Thanks
If you have a 230 SLK 1998-2000 aka "pre-facelift" model,your compressor is engaged by a clutch (wheel right next to the idler pulley), usually when rpm > 2,000. A fried/worn clutch might announce its illness by rattles. On the other other, if you have a post 2000 aka "facelift" SLK230, you'd only have a simple pulley wheel there as the compressor is driven at all times. How many miles do you have on the car?
 
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