C230 Sport Coup

Hmmmmmm...sounds like an exhaust leak...
which if the honeycomb material is shifting around, might have been plugged up, and the exhaust was pushing it's way out of any place it could.

How many miles on the car? A new cat might be in your future.
Check the tail pipe for tell tale grey dust.

PA_Pete

Almost 63,000. Yeah, I'm not looking forward to what that might cost it it's a new cat! Bought the car in July, I'm the second owner, and I'm guessing it's the original exhaust on the car.

Glyn M Ruck

On better speakers it seems to have a more puffy edge to the sound so might be an exhaust leak. What worries me is how loud it is. When you take the phone out from under the car & up the side it still very audible. (not what I would consider a tick) - What I find strange is that it does not tick faster as you rev up the engine - are you saying that it has no relationship to the firing of the engine?????

C230 Sport Coup

63K I wouldn't think it's a cat....

rploaded

I had that same sound on my old C class. Ended up being a small leak on a weld in the exhaust. If you can jack it up use a wet chamois and work it down the exhaust. When the noise subsides you have found your weak link.

Good luck things like this can be a real PITA to fix.

bumpnzx3

i am with E- i am guessing motor mount. seems i have read about a fair amount of C's having this issue. in gear- there is a load on the engine itself- so the chances of it moving would be a little less.

might be a torque converter bolt also. a friend's dakota had a noise similar to the noise/timing you are describing. then again, as glyn mentioned- my tick is your clank.

PA_Pete

Okay, after having this noise since I started this thread, I have concluded that it is in fact the exhaust. First I'll start by saying why I thought it was the transmission, while under the car today, I noticed that the exhaust hangers in the front of the car bolt up to a rear transmission mount (I have pictures, I just need to send them from my phone). The noise would subside when I engaged the transmission in gear, because the exhaust is connected to the rear trans. mount! While under the car, I removed the exhaust from the resonator back, so basically right after the secondary cats. With what was left of the exhaust system still attached to the car, I shook it and heard the noise in the passenger side secondary cat. I now know that the honeycomb in there must be loose. ALSO, while driving last night, I got a CEL, yup, I'm guessing it's from the cats. internals blocking up that ride side exhaust and causing the gasses to make the O2 sensor go crazy. I even had the CEL flash a few times! All of this and a huge lack of power. Again, I have some pictures of what I am talking about. Now, does anybody know what the warranty is on the emission system? Not from MB, but isn't there one that the Gov't. has, where if the emission system fails on your car while under 100,000 miles or 10 years the dealership HAS to fix it? If anyone knows, please let me know, I'm going to do a search now. If you read all of this, thanks!

EDIT: Found the website describing detailed information on the EPA's Emission Control System warranty, check it out!
http://www.epa.gov/obd/warranties.htm#a

Glyn M Ruck

I'm pleased you are winning !!!

PA_Pete

Thank You! Okay, as I promised, here are the pictures I took while under the car. They're nothing special, just a few snapshots of what I was doing. At this moment, my car is at the MB dealership getting the required service done to correct the Emission Control System defect.

First Photo: Here is the exhaust system from the connecting point back. Kinda heavy.
Second Photo: Here are the three bolts I had to cutoff, these were the bolts holding the front and back section of the exhaust together.
Third Photo: The secondary cats.
Fourth Photo: Where the front exhaust hangers mount onto the rear transmission support.

PA_Pete

Okay, my car is done, I picked it up today from the dealership with a new cat. replaced for free under the warranty that is put in place by the EPA. Now however, I do have other issues. Still getting a CEL. Dealership said they recommend me replacing the MAF, and that it is causing the Air Fuel mixture to be off, so I'm guessing that's what is triggering the CEL. They want $646 for that (not sure if that's labor or not). I'll do it myself for that price.

Glyn M Ruck

Interesting - all that noise from a shot Cat. I think I have bad news for a friend of mine who has a vehicle heading the same way. We have no such EPA safety net!

PA_Pete

Oh my, yes, not good for your friend. It was indeed the cat. The dealership confirmed that. The noise was getting more frequent the longer I let it go, as if more of it was coming loose. Wierd.

Glyn M Ruck

Well I've learned something. Thanks for the recording. I've saved the clip. By a process of elimination it had to be the exhaust but the noise is surprising. Maybe amplified by the auto gain control on your camera mic.

PA_Pete

True, very true. And as I said in my beginning posts in this thread, I myself thought it was the transmission. Which I mentioned earlier why I thought that. When put into gear, the noise would get quieter or go away completely. After being under the car and seeing that a set of exhaust hangers connect to the transmission mount, I know now why the noise would change.

PA_Pete

Of course I find this today after I post this huge long thread. Anyways, for anyone that was following this thread, check out this one:
https://mbworld.org/forums/showthrea...eplacement+maf

Seems as though he was having the EXACT same problem as me, but maybe a little worse since it stalled out his car and had to have it towed.

Glyn M Ruck

I think your thread will be of more help to others that experience this failure.

PA_Pete

Bringing this one back everyone. I just had the same exact thing happen to me again... on the drivers side exhaust! Yup, I started hearing a slight rattle while at idle. The noise would increase slightly when giving the car gas. I got under the car with it running, same noise as before! DAMN IT. So, just today, I dropped the exhaust, which, was not fun. Every bolt and nut except for the two bolts that hold the cat onto the header had to be cut, they were all rusted on. Now, when I started this thread and dropped the exhaust the first time, I had to cut the bolts and replaced with new, looks like I'll be replacing the bolts again. Anyways, with this section of exhaust lowered, I can hear that the loose piece of catalytic converter is in the smaller secondary cat. Here is where I wish I owned a ton of tools such as a plasma cutter and a welder that could handle stainless. If I want to resolve this, I'm guessing I'll have to replace this section of exhaust with the cat. Does anyone know where this is available for sale other that MB? I found some that are supposedly OEM replacements on a website called Auto Parts Warehouse. If anyone can vouch for them, please let me know. Also, I'll try to get pictures and upload them. This was all done with the car on ramps and jackstands in my driveway, what a blast.

PA_Pete

Alright, crappy cell phone picture time. I just went outside and took these real quick. Again, this is the drivers side cat, note the upstream O2 sensor still in there, that thing would have been horrible to take out with that section of exhaust still bolted up.