Exhaust fumes when opening the window

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E30REDD
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Post Sun Feb 24, 2013 10:16 am

My car is in bad shape in the rear because I guess it's been smashed.



There's comming a lot of exhaust fumes in the coupe when I open the passenger window a little while driving. I believe the fumes are comming in from the trunk and then gets sucked out through the drivers window.
age
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Post Sun Feb 24, 2013 11:46 am

yea its usually a sign of a hole in the bodywork.
M40 rightness if you can get to 6000rpm noone can hear your tappets
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Post Sun Feb 24, 2013 11:48 am

age wrote:yea its usually a sign of a hole in the bodywork.
I assume the whole rear plate has to be replaced...
Grrrmachine
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Post Sun Feb 24, 2013 12:12 pm

It's probably easier to replace than to fix. There are plenty on here who have replaced the rear valance before, and they're quite easily available. The real cost is repainting it afterwards.
Jesus325iTouring
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Post Sun Feb 24, 2013 2:28 pm

Whilst the cause is obvious here in this case, an exhaust too short can do the same thing. My exhaust on an old W123 Merc estate was too short and was slowly gassing me whilst merrily driving up and down the M6. I couldn't smell it, but over the course of a month of driving up and down there I was feeling increasingly ill.
Having extended the tail pipe, all was fine and i ceased to feel like shit. :D
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Post Sun Feb 24, 2013 2:31 pm

Jesus325iTouring wrote:Whilst the cause is obvious here in this case, an exhaust too short can do the same thing. My exhaust on an old W123 Merc estate was too short and was slowly gassing me whilst merrily driving up and down the M6. I couldn't smell it, but over the course of a month of driving up and down there I was feeling increasingly ill.
Having extended the tail pipe, all was fine and i ceased to feel like shit. :D
I could actually try that. :)
Jesus325iTouring
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Post Sun Feb 24, 2013 3:35 pm

Something like this should do the trick.............

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:wink:
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Post Sun Feb 24, 2013 4:22 pm

Jesus325iTouring wrote:Something like this should do the trick.............

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:wink:
Exactly what I was thinking! :P
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Post Sun Feb 24, 2013 5:39 pm

the clue you give me here is the fact that it is worse when the window is opened, this says to me the cause of the fumes is likely from the gearbox area......allow me to explain!!!

when you open your window (or sunroof) you create a low/high pressure at that point as the stationary air in the car is at a higher pressure than the air travelling at speed just outside your window. now the higher pressure air will then find its way to the lower pressure, so it goes out the window this creates a sort of vaccum in your car. as your car is full of holes such as the huge one around the gearstick the air under the car (turbulant and not as fast as the stuff just outside your window) will try to fill that vaccum...so air is sucked in through mainly the gearbox hole...so any exhaust gasses here...ie where your donwpipes join the main exhaust will be sucked into the car...this is also the reason why your gearknob gets hot with the window open, and why your fag smoke flies easily out the window if only one is open...its called Bernoulli's principle and it also why airplanes fly and footballs bend like beckam.

but ofcourse the same principle woudl work with gasses in your boot.

So if i were you i would have a look at the exhaust around the gearknob area first, then get that natty exhaust tip!
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Post Mon Feb 25, 2013 7:34 pm

mrLEE30 wrote:the clue you give me here is the fact that it is worse when the window is opened, this says to me the cause of the fumes is likely from the gearbox area......allow me to explain!!!

when you open your window (or sunroof) you create a low/high pressure at that point as the stationary air in the car is at a higher pressure than the air travelling at speed just outside your window. now the higher pressure air will then find its way to the lower pressure, so it goes out the window this creates a sort of vaccum in your car. as your car is full of holes such as the huge one around the gearstick the air under the car (turbulant and not as fast as the stuff just outside your window) will try to fill that vaccum...so air is sucked in through mainly the gearbox hole...so any exhaust gasses here...ie where your donwpipes join the main exhaust will be sucked into the car...this is also the reason why your gearknob gets hot with the window open, and why your fag smoke flies easily out the window if only one is open...its called Bernoulli's principle and it also why airplanes fly and footballs bend like beckam.

but ofcourse the same principle woudl work with gasses in your boot.

So if i were you i would have a look at the exhaust around the gearknob area first, then get that natty exhaust tip!
Hmm, I've actually noticed that my exhaust is leaking very close to the lambda. Thank you :)