sinaa

hi everyone

i have 02 c240 117k on it and its been a month that im expriencing a very annoying rattling sound coming from bottem of car so i take the car to mechanic and he told me that inside has been damaged and i need to change the whole thing, i was wondering of any of you guys exprienced somthing like that??the noise is very annoying especially while accelerating

samaritrey

get recording

sinaa

wat do u mean by recording?

samaritrey

so we can hear the noise.or better description of what they want to replace. i am wondering if it is a bad cat with 117k it could be. luckily i am at 138 and still have no cat problems.

acr2001

Most likely a bad cat. but a recording would definitely help.

You could just go buy a generic cat (make sure it fits first) and have it welded in-place of the bad one (instead of replacing the entire segment which I think includes both cats). Much much cheaper that way.

sinaa

ok i have found a picture this not a benz but just to show you where the noise comes from as the mechanic told me somthing came loose theresry guys

sinaa

if still not clear i would go and record the noise

sinaa

thank for ur suggestion i think both cats are damaged and where can i get w203 cats from?any idea? thanks again

acr2001

Well, I believe there are 4 cats on the W203. I meant both cats on whichever side. There is a front cat and a rear cat on either side. Your choice is between replacing that entire side with a new factory spec part (this is what the dealer does) or slicing out the bad cat and welding a new one in.

For parts you can start by taking a look on www.rockauto.com for genuine mb parts (which aren't worth it for this) www.getmercedesparts.com has pretty great prices.

sinaa

thank you for the information by cat you mean Catalytic converter? its costs $900 for the right side and $438 for the left i wonder how much mb charges for the whole thing cuz mechanic told me both sides needs to be replaced

samaritrey

do you trust your mechanic? but it is possible that both sides are bad. the cats for this car are cheaper then my old car lol.

W203E35

I remember a wise member here once told me that cats brake easily. During hard bumps the inside cracks.

Before we jump to cats lets try to diag the car.
When you put your car in N and press gas gently (rev) do you hear this noise or is it when you are driving?

Do you hear the noise when you come to a stop?
Is it a ticking noise?
A whistle? A screech?

sinaa

yes when i put the car in N and press the gas i can hear the rattling it sound like somthing is loose in the exhaust and also while driving i can hear it all the time i also hear the noise at stops but not as much, sounds like empty pop can thats shaking in the exhausts

sinaa

i showed the car to a few ppl all said the whole thing has to be changed but they werent really experts about exhaust job and replacing cats

Glyn M Ruck

It's likely that a piece of honeycomb has broken loose in one of the Cats. If the noise is where you indicate in your pic then either the piece of honeycomb has got stuck in a resonator or there is a loose baffle.

There are two Cats on these cars with the O2 sensors on either side of them right up front on each exhaust. The things that people endlessly & incorrectly call secondary Cats are in fact resonators.

sinaa

thanks for the information now what do you guys suggest me to do?any one know how much it cost to get it repaired? its really annoying while driving, and why would somthing like that happens cars really clean inside and out??? never had a problem like this with my pervious cars which werent clean and low K as this benz

LILBENZ230

What does being clean have to do with a failed catalytic converter?

W203E35

See you have 5 items on the exhaust not counting the muffler (which I doubt has a problem)

(cat)--------(resonator (looks like cat) )-------_______{Resonator}---------[muffler]-
(cat)--------(resonator (looks like cat) )-------

I doubt it will be the cats because they are up there (not too close to the ground-break from bumps) I have a feeling it might be your resonator (that looks like cats).

You want the cheapest route then I would say just have them weld a pipe and remove the cat like resonators. They don't cause emission problems so you can pass smog.

What do you guys think what's the cheapest way to solve this problem?

acr2001

Oops.

This explains why our E class was making that noise from the "secondary cat" and then after some hard driving it went away. The chunk of the cat must have blown out of the resonator where it was banging around. Thanks as usual Glyn.

Glyn M Ruck

If you are sure of where the noise is coming from the go to an exhaust shop & have them replace or delete the resonators. Cheap start number 1. Your Cats are obviously effective or you would have a CEL showing

Glyn M Ruck

Hey - no problem - just heard it once too often & decided to correct things.

Srav44

I purchased a used 2001 C240, excellent condition, clean, one owner, 81k miles, Friday night. While driving home I noticed a whistling noise, which sounded as if it was coming from the passenger side dash. It starts at about 25-30 MPH and gets louder the faster I go. No change in the noise regardless of the heat on or off. It stops when the car stops then regains when moving. It's not brakes, motor or anything mechanical but seeks to be air is catching on something and whistling. It's not the hood ornament either. The dealer states they cannot figure it out however, they are a ford dealership and I think they don't want to spend anymore time or money on her.

My daughter is very sick and we spend 1300 a month in copays for her treatments and travel a lot. I cannot buy a car that needs extensive work later or a new car because of our medical cost. I left it at the dealer Saturday (less than 16 hours of buying it I returned it.). I told them until the annoying whistling noise is gone I will not take her. I'm hoping you can help as I really love this car and I feel the ford dealer won't know these types of issues or will not call the local Mercedes dealer to assist him in finding the noise.

samaritrey

RUN!!!!
Sorry to hear about your daughter I hope everything is going well. Please do not put your family at risk buying an old Mercedes if you don't have disposable income for issues. BTW I have one of the most reliable w203 c classes on here which is also an 01 and is amazing even now that I have 204,000 miles ( I drive way to much). Back on point though the 01-03/4 c class can have seriously expensive issues and even the maintenance can stack up if you can't work on the car yourself. If you are a DIY type of guy and have free time and $250 a month in emergency cash you could do it but with a sick daughter I hope you would rather spend time with her than fixing a stupid car. I know a civic or accord is no where near as fun and exciting but they are dead reliable and cheap to own as long as you find a good one. The other nice thing is that almost anyone can work on them and parts are extremely easy to find. This means less stress on your car and wallet which means more time to look after the important things.
Sorry for the rant I don't mean to scare you or disrespect your decision making I have seen many people come and go on here who buy an older c class and complain all the time about how much it costs to keep running and how much stress it is to keep it on the road and as having a family member going through chemo right now I know how important it is to have as little stress as you can. He got rid of all the fun cars and now drives really reliable cars just to have less stress.
If you do decide that the car is meant to be have them check the blower motor that is where it is located and open the hood and check to see if the ac filter is above the battery it could be missing and when you get going faster air could be rushing in and making strange noises. Also try to set aside around $1000 in emergency repair cash because if you can't work on the car yourself a trip to a dealer will be north of $250 just for driving in the door. The m112 engine in the c240 is extremely reliable as well as the transmission (automatic or manual). The issues with these cars is the electronics, front suspension, some parts costs and keeping up with the maintenance. If you want more details let me know glad to help but think about what I said.