Rattling noise: C230k

[Mike51809]

I have had my car for about 2 years now n ever since ive had it the car has mad a rattling noise when i let off the gas and under very very light throttle while cruising.. it seams to be coming from the right front and i look but find nothing. Any idea what it could be? Everything i find online is under hard acceleration and anything over hardly touching the throttle makes it go away. Any ideas?

[Goldeni245]

Could it be the supercharger? It's on the right front side and Starr's rattling when the bearing is starting to go.

[afronumeric]

I snipped the wire for the electro magnetic clutch coming off the super charger. it causes the check engine light to come on. I dont care. My super charger was not blown up for anything. and I dont want to rebuild the supercharger as its costly. After I disconnect the S\C .. I started to notice the same rattle on my A\C when its turned on.

As of now.. I am running n\a w\o super charger and its still plenty of power to pass cars on the freeway and to accelerate, I think the supercharger only added like 25hp and prolly 45lbs of torque. (random numbers thrown out) I did this to increase reliability as I heard these super chargers can sieze up and your car will be totally stranded so I figure I disconnect the SuperCharger before that happens ,and if I ever decide to rebuild it.. it wont cost as much in repairs.

[Mike51809]

Is there any way to see if its the supercharger? When i go under the hood n rev it past 2000 rpm i just hear the supercharger kick in but not the rattle. It only happens when im at a cruise n let off the gas or barely press the pedal then goes away and makes it hard to figure out lol Also i do have some blower fan issues and the ac doesnt get very cold anymore so maybe i have a compressor problem?

[afronumeric]

It is the super charger making the noise. its loud and noticeable at 1-5mph as the diverter valve is wide open and allows the rattle of the supercharger come out of the air release valve.

its very noticeable in parking lots when your going 1-5mph.

I have heard our eaten m45's have self containing oil. not sure how to check this oil. maybe it has dried up and would cure the loud rattle. from research, (this same S\C is used on the mini cooper S) the front and or rear bearings need to be replaced.

honestly if this car is your daily driver, the supercharger is useless. the 200lbs of instant torque is nice and the car is faily quick but for a daily driver and if you stay out of trouble, u should disable it for improved reliability.

the AC problem sounds like you have a slow leak. you can inject a can of UV type AC fluid into your system and use the supplied black light and glasses to detect the location of your leak. common areas to look out for are hoses with a tear, where the hoses connect to each other and the AC compressor itself where the pulley input shaft goes into the unit. Its better to fix this sooner then later before all of your AC fluid leaks out then your AC system wont turn on because the PSI is so low. AC systems are tricky, they have low and high sides..and require some experience. youtube videos help. if you empty out your AC system, its the law that you have to collect it out with a pump and put it in a storage cylinder where it can be desposed of. and your not to allow any air into your AC system as it causes condensation. i can go on and on and on lol.. if you have the money, make sure the mechanic fixes the leak before they recharge your system, get a written warranty. I had a friend pay hundreds only to have it leak out. hes a born idiot though soo.. ya

[afronumeric]

if you want to know if its the S|C for sure.. drive in a narrow alley or an area that has a wall on both sides so the engine noise can bounce back into your car with the windows down and drive a constant 1-5 mph, IIRC... the noise goes away at 8 or 9mph.

[Mike51809]

Its hard to know because of my exhaust lol Like ive never heard the sound in a parking garage where you think you would i just hear it spool and the exhaust.. thank you for all your replies! Ill try maybe unplugging it to see if it goes away then ill know for sure because i can only really hear it with the windows closed and the radio off. Ill look into that leak,part of the problem may be my fan going out because at the first speed it will go full blast then the next speed slow then the next speed it will go high low and vary then stay low so i think its on the way out lol

[Goldeni245]

how about this, how many miles does your W202 have on it?

The superchargers are known to go at about 100,000 to 120,000 miles. I have 153,000 miles on my C230k and the supercharger is fine, but I'm worried about it dying on me at any moment!

[Goldeni245]

how about this, how many miles does your W202 have on it?

The superchargers are known to go at about 100,000 to 120,000 miles. I have 153,000 miles on my C230k and the supercharger is fine, but I'm worried about it dying on me at any moment!

[Goldeni245]

how about this, how many miles does your W202 have on it? Another way to find out if it's the supercharger is to get a "car stethoscope" at a auto store and touch it to the supercharger while the car is on. Have a friend rev the engine slightly and listen into the supercharger with the headphones to see if it's making any weird noises besides the normal humming noise.

The superchargers are known to go at about 100,000 to 120,000 miles. I have 153,000 miles on my C230k and the supercharger is fine, but I'm worried about it dying on me at any moment!

[Mike51809]

I can try that thanks man, i have 156,000 miles on it now i just hope it lasts cuz its not ceap to rebuild or replace

[Goldeni245]

aww crap...I hope i'm not 3,000 miles away from a failing supercharger! Maybe now is a good time for me to sell it :,(

A rebuilt supercharger will not cost you THAT much. It will cost $650 max for a rebuilt one that will last a very long time. There are places that sells them for our C230ks, you can do a search. They do ask you to send them your old supercharger afterwards.

You can try ebay for a supercharger taken off a wrecked car, but it'd probably be better to pay a little more and get the rebuilt one. Installation shouldn't be that hard as I've seen, on Youtube, a guy remove and replace the supercharger on an SLK230 without much fanfare and from old threads, people have removed and replaced it themselves.

This would be the best route probably. As you can see in the photo, even though it is rebuilt, it looks brand new. Course you could just pull the clutch plug, but after getting used to the power of the C230K...i don't think I'd be happy at all with a normal 230. The kompressor just makes driving so much more fun.

Hopefully it's not the supercharger. It might be something completely different, it's best to take it to a mechanic if you still can't figure it out with the stethoscope. Don't just touch the tip to the supercharger, check every moving part to see if it's making strange noises.

[Goldeni245]

The Mercedes 2.3 liter is a hearty and reliable engine that can go well into the 230,000 mile range with normal fluid maintenance. (From what I've read, the original non supercharged C230 was one of the most reliable Mercedes engines in the line up.) $650 isn't much to keep the car running for a very long time. I mean, where are you going to get a new car for $650?

[Mike51809]

Well I honestly think it's not the supercharger, I went under the hood today and did the throttle with my hand where it would happen and nothing... it's only when I'm driving so something must be lose or something but I honestly don't believe its the supercharger. I watched the clutch engage just fine and it just wined like usual because of my intake lol It's very hard to diagnose since it only happens while at cruise. And you're right that is very cheap to keep the car going when it's very reliable, and well it's my baby. When I get the money I wanna completely rebuild it to make it last. Thank you for your insight! Oh and I turned the A/C on too just to make sure and nothing... tensioners are good and I just don't know what the heck it is

[Goldeni245]

that's good to hear man, makes me worry a bit less about my supercharger.

Keep us updated please!

[Mike51809]

I will, it's gotta be something loose but its hard to find unless I can be under the hood while someone drives lol

[Mike51809]

Finally figured out the rattle, after much hunting and suspecting possibly the tranny mount because i now experience vibration, i noticed that the flex disc was loose! The rubber had shrunk over time and did not bolt tight no matter how hard i tightened the bolts so the rubber would vibratr making the metal sleeves through it rattle... so happy i figured it out it drove me nuts and i thought there was something seriously wrong

[Goldeni245]

thanks for following up!

[Mike51809]

No problem, i knew you were wondering too lol

[melk]

Where is the flex disc and what is its function? I'd like to inspect mine.

[Mike51809]

The front one connects your output shaft of your transmission to your driveshaft, when you look its just a big black disc with 8 bolts. There is also a rear one connecting your driveshaft to the rear differential that is a little smaller and thicker but looks the same

[melk]

Ahh ok. So it's a rubber bushing of sorts. How much was it to replace?

[Mike51809]

The front is ebay $80 cheapest but autohausaz charges $100 but might be better quality and the rear is around $40

[melk]

Ok great, thanks. I'll keep an eye on this. Ours has 110k so far.

Glad you figured it out :)

I've heard some talk of something in the middle of the drive shaft? I haven't even picked up the car yet haha so I have a lot to learn.

Is it a two piece shaft? Or just one straight shot between the trans and diff?

[Mike51809]

Its a 2 piece driveshaft, theres a heat shield by the cats and under it is where theyre joined. Me too! You will probably fall in love with the car, i didnt like mine at first but it won me over lol

[Mike51809]

Update: put the new flex disc in today and got rid of the rattle and my steering wheel vibration coming through the engine through the frame! Also i gained some of my acceleration back i lost with all the vibration

[vaspen]

dude you may have helped me soooooo much .... u seen my thread in the repairs on maitnance job I have the part just waiting on a lift ... lol