Are you smarter than a MB certified technician?
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2006 C230 Sport
Are you smarter than a MB certified technician?
I have a pop/thump noise coming from the rear of my C230 Sport w/ auto trans when I am at a complete stop with the brakes applied and in drive. For example at a stop light or a drive thru. It starts with a soft noise like a click then 2-3 seconds later a very rapid series of thumps/pops happens then it goes away until I come to a complete stop again with the car in drive and the brakes are applied. MB technicians can't figure it out after $1200 in diagnosing fees. Hence the title of my post. I am new to the MB world so any help would be very MUCH appreciated!
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From: 1 hours drive north of Sydney Australia
2007 W204 220CDI Classic Sedan
I get a loud "grumble" type sound sometimes when light breaking & when almost stopped . It is pretty normal & caused by pad vibration . I think a pad grease may fix it but I have never bothered.
Try doing it with someone else driving with you standing beside or running beside the car. You may be able to pinpoint the location. I have to do this sometimes to find which disc stone guard has a stone underneath it !!
Try doing it with someone else driving with you standing beside or running beside the car. You may be able to pinpoint the location. I have to do this sometimes to find which disc stone guard has a stone underneath it !!
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Newbie
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2006 C230 Sport
Thank you guys for the input. I really appreciate it. Tee, have you had the same issue and did you fix it by working on the parts you mentioned? Carsy, thank you for replying but my issue occurs when I am at a complete stop with the brakes applied to keep the car at a stand still 
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From: California
E55,GL 450,Subaru STI,Chevy crewcab
Look at the purge valve it is located by the left front head light start the car and when you hear/ feel the thumping see if it matches the purge valve. Very common that people complain about this you can insulate it from the body better with felt tape and that seems to help. If it is the canister shut off they make more of a popping type sound from the r/r of car.
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Junior Member
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From: California
E55,GL 450,Subaru STI,Chevy crewcab
MBWorld Fanatic!
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From: WNY
2005 w203 C230
[QUOTE=leonelalbarran;5944536] MB technicians can't figure it out after $1200 in diagnosing fees. QUOTE]
Did you pay them $1,200 for nothing?...Did they take $1,200 for no work rendered/issue resolved?
Did you pay them $1,200 for nothing?...Did they take $1,200 for no work rendered/issue resolved?
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2006 C230 Sport
They connected the OBDII machine. Took a look at the car. Lifted it up and looked underneath. I mean they have tried but after 3 attempts of looking with no results is just hard to believe lol.
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Newbie
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2006 C230 Sport
Thank you all for the replies. Quick question for you tee, would this sort of thing not throw a code? That is one thing I forgot to mention in my original post. The computer is not throwing any codes....
Junior Member
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From: California
E55,GL 450,Subaru STI,Chevy crewcab
It will not throw a code because the valve is working. You could unplug the purge valve and drive it to see if the noise is gone but doing this will store a code.
Senior Member
Joined: Sep 2006
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From: Northwest Arkansas
2016 C450
Sounds to me like you are describing the tapping of the charcoal canister. They are loud on 203 sedans particularly and Mercedes has released a small aluminum machined sound dampener that is installed inside the rubber hose to the charcoal canister. It dampens the light clicking/tapping sound from the RR of the vehicle. Give it a shot, the part is really cheap.
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
That is extremely interesting. All SA built W203's had those, Well certainly my old 2003 C240 had one. SA cars also had a rubber pad under the bracket that bolts the purge valve to the shock tower.
So it's the restrictor that damps the purge line. Makes a lot of sense.
In that case unplugging the purge valve would confirm it's the purge circuit that's transmitting the noise.
I would definitely fit one.
So it's the restrictor that damps the purge line. Makes a lot of sense.
In that case unplugging the purge valve would confirm it's the purge circuit that's transmitting the noise.
I would definitely fit one.
Senior Member
Joined: Sep 2006
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From: Northwest Arkansas
2016 C450
It's not really a well known fix, even at the dealership level. The amount of affected cars seems very small so the info isn't well known among techs or service writers. His symptom sounds exactly like this issue.
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Indeed they do! Thanks for the info!
BTW ~ (listed in the EPC as 35 A 203 476 03 32 VALVE REGENERATION LINE 001) no picture.
BTW ~ (listed in the EPC as 35 A 203 476 03 32 VALVE REGENERATION LINE 001) no picture.
Last edited by Glyn M Ruck; Feb 20, 2014 at 09:44 PM.
