It could be one of so many things. Can you narrow it down to engine area, transmission area, driveline area, rear end area? Did this just start after you did your motor mounts? If not, did it change after you did your motor mounts? Did you do the transmission mount when you did your motor mount?

 

This problem has always been there since I've had the car. I just purchased this car used about 3 weeks ago.

I've had the car looked at by two mechanics and neither one of them mentioned anything about it. It might be only when it's cold, but nonetheless, it's been there since I've known it. But then again, they both didn't really drive it around.

The grinding noise is coming from the engine bay. Not sure exactly where, but seems from the lower part. But its for sure there when I accelerate for a little bit.

I also did the tranny mount too, but again, the noise was done before any work was done on the car.

 

Can you get the noise by accelerating in park or neutral or does the car have to been in gear and accelerating under load? If you can get the sound in neutral, can you open the hood an manually move the trottle pedal cable from inside the engine compartment and help isolate the sound to a specific area? Maybe it is something simple like a belt that is slipping due to a tensioner that is losing its strength or maybe the tensioner bearing is going bad? Does the grinding sound increase/decrease in speed with the engine speed? If you can set up your digital camera and post a video on youtube with quality sound, that might help us diagnose things.

 

Wow, your going to have to isolate the noise down as mentioned above. This could be many different things. My first thought was a sticking caliper but you said it was in the engine bay. Here is a link about the SC "oil being low" with also a link at the bottom with more info.
http://www.benzworld.org/forums/w20...rums/w203-c32-amg-c55-amg/1489049-c32-amg-2003-supercharger-horrible-noise.html

I would also take the serpentine belt off and inpect the pulleys, the a/c comp. clutch can make sounds like you mentioned as well. B

 

Still trying to isolate the noise...but here is what i've found so far...

1) It is not the silver dimple protection from underneath. checked all of them and although some of it did make noise, i have remedied anything that would remotely make the sound. Test drove again, still making noise.

2) it does not make the sound in park or neutral. In reverse it does and in drive it does.

3) the noise is prominent from 1250 RPM to 1800 RPM. Goes away outside of those parameters. Within those parameters, it does it in 1st, 2nd, and slightly in 3rd gear. I cannot get it to go into 4th or 5th gear at that low of rpm.

4) I will try to get video soon. It's hard to locate the actual noise cause the car has to be in motion. With my windows rolled down, i can definitely hear it well from the drivers side. To describe the noise a little more, it's almost like a subtle version of a diesel engine/ tiny pebbles being dropped into my tranny.

 

You know, I have noticed a similar noise recently in my '98. Almost the way a bad CV joint sounds on a front wheel drive car. It's more pronounced when it's cold or first started, and seems to be louder when making turns and is effected by speed. I'm thinking it's the tensioner pulley getting ready to fail. It nearly goes away once the engine is warm and is not noticeable at all while cruising. Going to dig deeper when this snow melts...

 

Yeah, it's a little like that sound, but more pebbly.

I have found that it is NOT the shifter linkage bushing...

 

i went to a benz mechanic who drove with me around the block. he thinks it's the catalytic converter making the noise. I tried banging the cat but there is no noise coming from it...

still on the search... or could it be it?

 

Hi my name is Johan and I had the same fault on my c200 1999
Im new to this so hope to be of help Replace your fan belt tensioner shock This cost me 350 zar and 10 minutes labour and all noise went away Checking it is easy to Let the car idle and you should see the shock moving up and down

 

So, after much searching, I have found that the culprit is the pulley on the alternator. Its the very left side pulley looking into the engine bay from the front of the car.

I have not fixed it yet, but I was hoping someone here has any insight on how to fix it.

I tried to tighten the bolt as hard as possible, but it's hard to do since there's very little room and the grip on the pulley is weak.

Do i need to change it out? Figure out a way to tighten it more? Or is this an internal issue inside the bearings of the pulley?

Any advice is appreciated!

Thanks

 

was looking to see if the alternator pulley truely was the issue...

 

Check your ATF level- it could be low... Torque Converter may be draining... Do you have car power problems?

 

Check your ATF level- it could be low... Torque Converter may be draining... Do you have car power problems?

 

I had the same issue on my 95 220 it was the tensioner. I replaced it and the pulley for under $80. If you use the search there is a good DYI on how to do it.

 

i have exactly the same noise in my 99 c230 kompressor!! are you sure thats what it is? when pulling the throttle cable and listening I've heard the noises around the supercharger (electromagnetic clutch area) to be specific... cause the noise is kind of grindy but also like a computer hard drive type noise...

I also found a rebuild kit for 60 bucks including new s/c oil and the bearings for the snout..

but maybe I am wrong...

 

update?

 

Could be camshaft positioning, or something wrong with the engine timing?...

 

I have a 1998 C240T with 172000km which does the same type of noise but only when cold. On accelerating over a certain speed, the noise disappears. When hot and at low speed and turning right the noise comes back. I recall that the noise appeared soon after having the ATF and filter changed. IMO the noise is coming from the lower part of the engine compartment (tranny tunnel area?).

Well after a 10 day break during which the car has not been used and now that the weather is warmer, took out the car this evening and guess what? NO NOISE!!

 

It must have been the Torque converter, please check your Transmission Fluid level again to be sure you do not get the same issue later...

 

Hey guess what? The noise is back! Weather has been much colder again these days and the noise has reappeared when accelerating with cold engine and transmission. Stops when engine has warmed up. Will definitely follow up and check the ATF level (hot) with my new dip stick I just purchased. Further report soon.

 

Also check if your fuel is alright just in case.

 

Hi All! I have a 2010 C 300 Sport, and am hearing a metallic grinding noise when accelerating -- but only when the car has warmed up. Any idea as to what it could be? Thanks!