Strong burning smell

KNG 1953

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C Class (W204)/2010/CDi220
I have an 8 month old C Class 220 CDi (W204) Sport Auto BlueEFFECIENCY Saloon which I purchased new. It has been back to the dealer on 4 occasions because of a very strong burning rubber smell from the left hand rear side of the car. Mercedes have told me to live with it as they have no intention of doing anything about it even though it is a known 'issue' and they know what is causing it. They say the smell is caused by the exhaust getting extremely hot which causes the resin in the rubber exhaust bushes to overheat. This overheating is caused by the engine 'cleaning' the Diesel Particle Filter in the exhaust. I have to say I am amazed that a Premium car maker such as Mercedes produces luxury cars that smell like a burning tyre dump. I have told the dealer I didn't pay the thick end of 30k to drive around in a car that smells like it is going to burst into flames at any moment, but they just shrug their shoulders and say there is nothing they can do about but Mercedes 'assures' me it is not dangerous and the car is safe. Call me a sceptic but that does feel with much confidence. Does anyone else have a similar problem or am I just unlucky and have a Friday afternoon car?
 

Njmotors2011

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w210 96 3.0d w901 311cdi ml 270cdi Sierra sapphire cosworth
This is probably one of the worst smells from a car as an ex exhaust fitter ive never known this before the only way an exhaust would get that hot if its blocked have you seen a drop in power id keep on to them.
 

bahram

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C class w203 c200K 2004
I have an 8 month old C Class 220 CDi (W204) Sport Auto BlueEFFECIENCY Saloon which I purchased new. It has been back to the dealer on 4 occasions because of a very strong burning rubber smell from the left hand rear side of the car. Mercedes have told me to live with it as they have no intention of doing anything about it even though it is a known 'issue' and they know what is causing it. They say the smell is caused by the exhaust getting extremely hot which causes the resin in the rubber exhaust bushes to overheat. This overheating is caused by the engine 'cleaning' the Diesel Particle Filter in the exhaust. I have to say I am amazed that a Premium car maker such as Mercedes produces luxury cars that smell like a burning tyre dump. I have told the dealer I didn't pay the thick end of 30k to drive around in a car that smells like it is going to burst into flames at any moment, but they just shrug their shoulders and say there is nothing they can do about but Mercedes 'assures' me it is not dangerous and the car is safe. Call me a sceptic but that does feel with much confidence. Does anyone else have a similar problem or am I just unlucky and have a Friday afternoon car?

My very limited understanding of this is that DPF is part of Euro 5 emissions reduction regulations effectively imposed on post 2009 cars. It works by trapping the soot and burning it into ash and reducing emissions in this way. So when the level of soot in the trap reaches a pre-set limit the ECU adjusts fuel injection timing so that the exhaust is operated at high(er) temperatures and the soot in the trap is burnt. So the burning smell could be the soot being burnt off and also maybe it is the exhaust rubber bushes overheating. Different materials / design of bushing may cure this in future.
Is the smell very alarming and unpleasant?
 
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KNG 1953

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In answer to NJMOTORS2011 and bahram, thanks for your comments. There is no drop in power or any other physical sign. The car drives perfectly normally the whole time. In fact apart from the smell, the car is brilliant. The smell is only unpleasant if you don't happen to like the smell of burning rubber. I can only smell it when the car is stationary and either of the passenger side doors are opened but it dissipates after a few minutes. The dealer has quoted to me what Mercedes has told them and they say it's all to do with Euro Emissions Regs apparently. I was also told replacing the exhaust rubbers will make no difference as it will happen to the replacements and is a 'characteristic' of the car, which I think is a load of BS. The dealer also told me he had another customer tell him yesterday that his E Class is suffering from the same malady but I don't know whether to believe them or if they are pulling my chain to try and make me feel better that my car is not the only one affected. I think I can feel a letter of complaint coming on with a copy to Auto Express for good measure. The dealer has looked at the car 4 times since I have had it, to find out what was causing the smell.
 
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KNG 1953

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This is one of many posts I found on this type of smell when I searched in google:

http://forums.tdiclub.com/showthread.php?t=294807

Looks like it is not the exhaust bushes but the smell of DPF burning the soot and so called 'regenerating'.

I am just beginning to learn this having also done a bit more research since I posted my original comment. Aside from the post you provided a link to, the problem seems quite widespread, so I guess I will have to put up with it. Perhaps a clothes peg might be the answer or don't buy a car with a Diesel engine again.
 

dieselman

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No winging letter to Auto express, then?
 

bahram

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I am just beginning to learn this having also done a bit more research since I posted my original comment. Aside from the post you provided a link to, the problem seems quite widespread, so I guess I will have to put up with it. Perhaps a clothes peg might be the answer or don't buy a car with a Diesel engine again.

Yes it is reminding me a bit of the smell of rotten eggs of early Catalytic converter cars we all used to experience whilst reversing with window open!. That seems to have improved a lot and modern Cats don't smell as much. Apparantly DPF is very efficient in soot reduction (up to 90%!). So whilst you experience the unpleasent smell occasionally your car is doing its bit to reduce global pollution :)

Enjoy your new car and welcome to the forum. :)
 

dieselman

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So whilst you experience the unpleasent smell occasionally your car is doing its bit to reduce global pollution :)
You mean local pollution. The DPF actually increases global pollution.
 

bahram

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You mean local pollution. The DPF actually increases global pollution.

How does it do that DM?? :confused: Those guys imposing European emissions standrads then must be just passing it on from Europe to other parts of the world?:shock: How is it increasing global pollution?
 

dieselman

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Any exhaust restriction causes the engine to work harder so burn more fuel, with the resultant increase of Co2 output. A DPF is the worst restriction an exhaust will see.
in addition the DPF is regenerated by using waste fuel to overheat it, thus more fuel used, and the particulates that were trapped are expelled at that point in one big cloud, so even the local pollution is back as it was, but more concentrated.

Whoever thought up fitting DPF needs to be locked up for a long time, they are a danger to themselves and the rest of mankind.

Left to their own devices modern diesel engines create such low emissions the only thing we need to concentrate on is fuel efficiency.

The old adage of you can't gas yourself with a diesel engine still holds true.
 

bahram

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Yes DM interesting way of looking at this. The restriction in the exhaust would make the engine work harder and burn more fuel which in turn leads to increase of Co2 emissions. I think maybe they would have taken this into account when imposing such stringent regulations on particulates to make OEMs fit DPfs.
I like the idea of locking some of these guys up for a long time though! EU Buraeucrats!!:lol::lol:
 

dieselman

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I think maybe they would have taken this into account when imposing such stringent regulations on particulates to make OEMs fit DPfs.
Removing particulates from diesel exhaust was a political issue, not a scientific one. The media drove a misguided attack on diesel emissions and the public believed them and politicians buckled to pressure.
people were led to believe tat because they can see smoke emission from diesel exhaust it must be harmful, whereas petrol engine emissions aren't because they can't be seen readily...

One of the studies cited was conducted in an American town. it said that on days where the atmospheric and traffic conditions combined to give high particulate readings more susceptible people suffered from lung problems.

What it failed to mention was that there were no diesel engined vehicles in that town, even the buses were petrol engined.
 

Vendo987

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C-Class/2011/250CDI
I am sufferring same issue as KNG, this thread and related links has been very helpful, my new C-Class sport 250CDI with 12miles on the clock 'stinks' - strong burning smell from the rear etc, I checked everything and could not figure it out, thought it might be new rubber or dust on the brake discs. Luckily smell has occured only twice (ie an intermit basis), this week things are normal. I have shared this thread with the MB dealer, if problem persists I will take it up with MB servicing.

..Vendo.

Many thanks as I am new member.
 

j mather

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W220 Sclass 320cdi plus w221 350 blue tec
Same symptoms on my 350 cdi--it also has very loud heat contracting noises from the exhaust on engine shutdown----after posting this a few weeks ago I think it was dieselman who provided the explanation--don"t worry MB will look after us if there is major cost failure !:)
 

Robert Cairns

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E Class Coupe Auto 2013 220CDI
I have an 8 month old C Class 220 CDi (W204) Sport Auto BlueEFFECIENCY Saloon which I purchased new. It has been back to the dealer on 4 occasions because of a very strong burning rubber smell from the left hand rear side of the car. Mercedes have told me to live with it as they have no intention of doing anything about it even though it is a known 'issue' and they know what is causing it. They say the smell is caused by the exhaust getting extremely hot which causes the resin in the rubber exhaust bushes to overheat. This overheating is caused by the engine 'cleaning' the Diesel Particle Filter in the exhaust. I have to say I am amazed that a Premium car maker such as Mercedes produces luxury cars that smell like a burning tyre dump. I have told the dealer I didn't pay the thick end of 30k to drive around in a car that smells like it is going to burst into flames at any moment, but they just shrug their shoulders and say there is nothing they can do about but Mercedes 'assures' me it is not dangerous and the car is safe. Call me a sceptic but that does feel with much confidence. Does anyone else have a similar problem or am I just unlucky and have a Friday afternoon car?

I have a 2013 E Class AMG coupe with exactly the same problem. An intermittent burning rubber/electrical smell and then sometimes a puff of smoke from the front grill. I contacted the dealer and was told this was quite normal and designed to do that. I agree for a £40K luxury car it isn't really acceptable.
 

Coops123

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E Class 220d 2017
I have an 8 month old C Class 220 CDi (W204) Sport Auto BlueEFFECIENCY Saloon which I purchased new. It has been back to the dealer on 4 occasions because of a very strong burning rubber smell from the left hand rear side of the car. Mercedes have told me to live with it as they have no intention of doing anything about it even though it is a known 'issue' and they know what is causing it. They say the smell is caused by the exhaust getting extremely hot which causes the resin in the rubber exhaust bushes to overheat. This overheating is caused by the engine 'cleaning' the Diesel Particle Filter in the exhaust. I have to say I am amazed that a Premium car maker such as Mercedes produces luxury cars that smell like a burning tyre dump. I have told the dealer I didn't pay the thick end of 30k to drive around in a car that smells like it is going to burst into flames at any moment, but they just shrug their shoulders and say there is nothing they can do about but Mercedes 'assures' me it is not dangerous and the car is safe. Call me a sceptic but that does feel with much confidence. Does anyone else have a similar problem or am I just unlucky and have a Friday afternoon car?
Thank you and others for posting this message. I bought my E Class 220d in June but because of Covid have done few long journeys. This week we did a 300 mile round trip to the coast and when I came to garage the car there was a smell as you describe. I also noticed that the bodywork on the left side front was hot. I think you guys have nailed it but it is disappointing
 

LostKiwi

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Thank you and others for posting this message. I bought my E Class 220d in June but because of Covid have done few long journeys. This week we did a 300 mile round trip to the coast and when I came to garage the car there was a smell as you describe. I also noticed that the bodywork on the left side front was hot. I think you guys have nailed it but it is disappointing
You'll almost certainly find it's the DPF doing a regen.
During a regen the DPF is heated to a high temperature to burn all the soot and particulates it's captured. This heat is most likely what you experienced. A regen is most likely to occur during a long trip as all the parameters required to start one off are easier to meet.
 

BrianZ

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I have 2014 ML350 (bought it new). (Even after 8 years, I still smell the (plastic) burning smell especially when the sunroof is open. It is less smelling when AC is on. The burning smell makes me nauseous. I visited the local dealerships multiple times but they could do nothing.
 

sausage

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Tuppenceworth.

Vendo: With a car with 12 miles on, could you just be smelling production chemical residue burning off various components and it will clear in time? We often need to wash kitchen items before first use and a car is a lot more complex. I have smelt chemicals on some new clothing that required a wash before first use.

Both. I would have expected dpf regen to only occur at a certain rev range. I would take it for a long drive and keep the revs up above the level where the regen kicks in and I would do it for a while. The manual or the web might inform you of the rev range and the duration. I would exceed the duration and attempt to give those pipes a good clean out.
 

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