Hey guys,

Please help me. I'm experiencing a rather annoying rattle and it all started after I got my OE Tune but could definitely not be related.

A bit of background:

One month ago I did a resonator delete and replaced with stainless steel straight pipes. Last Thursday I did an OE tune to run 98 octane fuel. In the tune they programmed it so that I would also do a secondary cat delete and replace with an X pipe (basically to not have the warning light come on the dash). All was OK until the day before yesterday when I was driving on a pebbled (cobbled) road. This does not happen on straight / smooth roads.

When the car is driving over uneven surfaces and bumps, there's a rattling sound. It sound's like metal is hitting metal. I thought it was a leak where they put the straight pipes. But checked the complete exhaust system and no air was leaking or so I was told. While it was at the exhaust shop I decided it was time to do the secondary cat delete and replace with an X pipe which I did. At the same time there were some loose bolts in my car where the spare wheel was so thought that's the sound. Removed them and still coming.

If drivers window is open it's very loud but only on uneven surfaces when suspension is in big motion and it sounds like it's coming from the front quarter of the drivers side of the car. If I close the driver's window and open rear passenger window on driver's side, the sound is there but a bit quieter. If I close both windows on drivers side and open any window on passenger side front or rear, the sound is almost non existent.

Do you have any ideas what this could be? It's driving me insane and sounds like an exhaust clamp is loose or the exhaust is dragging on and off the ground. Although all exhaust clamps checked and OK.

Any ideas?

Please helP!

 

How many KLM are on the car?? I had a similar issue with my 2009 c63 sedan at around 50,000 klm and it turned out to be Baffles in the muffler.

MB replaced under warranty and all was good.

Long shot but worth a check>>>>>

 

Thanks North, Right now just over 60,000kms on the clock. I will definitely check that out. Mind me asking what's baffles and is it easy to check for?

 

(Ref: eHow)
Exhaust Baffle
The exhaust baffle is a chamber inside a muffler or resonator that is designed to muffle or silence the otherwise loud exhaust system. Ingeniously, the muffler uses the baffle chamber to increase the amount of internal sound inside the chamber so by the time it exits the muffler, the sound cancels itself out. Exhaust is spent fuel and air of an internal combustion engine and is extremely loud coming from the cylinders of the engine. An exhaust system controls the sound through a manifold and a series of pipes, a catalytic converter (on vehicles) and the muffler. In some applications, resonators are present in the exhaust pipes that act as a second (or more) muffler on the system. Inside the muffler or resonator is a sealed chamber with two or more perforated tubes. The inlet perforated tube allows the exhaust to emit into the baffle chamber, bounce off the interior walls and enter into the outlet perforated tube where it is then directed by back pressure through the tailpipe of the muffler. The perforated tubes in the baffle chamber create a nondirectional interference with the flow of the back pressured exhaust and assist in silencing the exhaust.

Read more: How Exhaust Baffles Work | eHow.com http://www.ehow.com/how-does_5044307...#ixzz2HUO4fOIW


To check you can use your fist or rubber mallet to bang on the muffler. If it rattles thats the culprit>>

 

Thanks North,

I'm certain I banged and tapped every part of the exhaust system and nothing seemed loose.

What I don't get is I have no resonator but this problem only happened 30 days after removing it and secondly it only happens on bumpy roads and third it only happened after the tune (that said, I didn't go on bumpy roads for a while before the tune so can't pinpoint when it started). If I raise the car on a lift and floor it, no rattles, no air leaks. There's no resonator and now now secondary cats so it's either primary cats or mufflers or something else all together. From where the sound seems to be coming from (loudest when driver's window down), I'd say it's more primary cat side than muffler side of the car.

Will raise again tomorrow, take off drivers side front wheel as well and check everything again.

The last thing I want is to spend a few thousand dollars for someone to take everything to pieces just to find out what the problem is. Going to upload a video clip of the sound soon.

Thanks again for your time.

 

Gremlins>>>>>>

 

haha

OK so here is a clip of the sound. It's driving me INSANE. This is at speeds of 10 - 15km/h on pebbled / cobbled / paved bumpy roads. Something is wrong but no one knows what

PLEASE HELP

http://www.youtube.com/watch?v=jtdkJqY7PSc&feature=youtube_gdata_player" target="_blank">http://www.youtube.com/watch?v=jtdkJqY7PSc&feature=youtube_gdata_player

 

That's my arm / hand, holding the iphone near the window / wing mirror but keeping the phone inside so the air doesn't blow in the mic and take away all the sound. The quiet part in the vid is where the road becomes smooth for 15 meters before going bumpy again. PLEASE PLEASE HELP. REWARD OFFERED

 

Thats nuts!! Sounds like a Heat Shield ..

I may be in Dubai end of February so if its still there I would be happy to try and help locate the source

 

Thank you so much North, I will take to my AMG specialist tomorrow and see if he can check the heat shield and to see if there's anything there that can be causing it.

If not, really appreciate your offer if you're out in Dubai. Can show you the beast and take you for a beer / meal.

 

It literally sounds like you're driving a shopping cart! Hope you get that fixed!

 

Me too Larry,

only a shopping cart on those bumpy uneven roads, otherwise on a normal highway or road, sounds like I'm in a Mclaren F1

I hope I get it fixed too!

 

Got to be exhaust related, given the noise coincides with getting the exhaust work done. Maybe a missing exhaust hanger or something, so that the exhaust system is hitting a fixed part of the bodywork like a heat shield or the diff.
Need to get it on a hoist and check for loose or missing hangers and when cold of course hold the exhaust with both hands and give it a good shake around to try to reproduce the sound. You could also use a rubber mallet to give the mufflers and pipework a good whack to see if there is anything loose.

 

Geez, that is a very LOUD noise!!!!....so, IMHO, once you get an expert on the job, it should not be hard to locate & fix.
Cheers, Pickles.

 

Do you still have the cross brace, in front of the resonator, bolted to the under-body of the car? The stock pipes curve a little to go over it. Sometimes replacement pipes are too straight and hit the cross brace.

 

Woooohooooooooo,

Lifted the car and removed the front wheel. The problem was the cover that protects the suspension etc from the brake disc. There's a metal cover on the rear of the disc, don't know what it's called but it was not secure and rattling as a result. Problem solved!

I can get back to enjoying the music of the resonator and secondary cat deletes.

 

Glad you solved the issue. Happy trails>>>>

 

How did that shield get loose? Glad to hear you solved the problem.

OK back to the music.