exhaust fumes?

[kusanku]

I've been getting something strange every now and then on my C220 cdi. On about 3-4 occasions now, I've pulled up with the engine running and have been horrified to see what looks like steam coming from under the bonnet. The temperature guage is fine and no warning lights. However, the emerging cloud smells as though it is exhaust fumes rather than steam. I've not been able to track down where they are coming from, although I think it is drivers side. I don't think it's as straightforward as a leak in the system, otherwise I would be getting it all the time. Took the car to my local speciallist, where the car behaved perfectly, and nothing seemed to be amiss. Has anyone got any suggestions?

 

[lotusmark2]

I've been getting something strange every now and then on my C220 cdi. On about 3-4 occasions now, I've pulled up with the engine running and have been horrified to see what looks like steam coming from under the bonnet. The temperature guage is fine and no warning lights. However, the emerging cloud smells as though it is exhaust fumes rather than steam. I've not been able to track down where they are coming from, although I think it is drivers side. I don't think it's as straightforward as a leak in the system, otherwise I would be getting it all the time. Took the car to my local speciallist, where the car behaved perfectly, and nothing seemed to be amiss. Has anyone got any suggestions?

Think I remember something to do with an aux heater in the front wing area, and this being normal in cold weather, I may be totally off track but worth a search on here under "aux heater"

EDIT: In fact the more I think of it, the more I'm sure that the aux heater thing was not on a C Classs. I'll just get my coat.

 

[jaymanek]

the c class does have the aux heater aswell, if it has the rest function... but doesnt sound like that though?

 

[Dieselman]

Definately sounds like auxilary heater which will come on while the engine is still cold.

 

[kusanku]

My car does have an aux heater. I've tracked down where the fumes are coming from, are a particularly vigorous bout of emissions yesterday. There is a pipe on the drivers side, about 4 inches in from the side, midway between the headlight and front wheel. Looks like an outlet of some kind. Fumes were absolutely poring out of it, which were highly visable because it was a cold day. I would have taken the car in, but needless to say next time I used it, there was no trace of anything amiss, and there hasn't been since. Does anybody know what this pipe is connnected to? I suspect it must something to do with the turbo, but not at all sure.

 

[Satch]

My car does have an aux heater. I've tracked down where the fumes are coming from, are a particularly vigorous bout of emissions yesterday.

If you have an Aux heater, may be that pressing whatever buttons puts you in "Aircon Off" mode will also turn the Aux. heater off as well. Certainly does so on my diesel E class.

If so, choose a cold morning & you should be able to find out if this is the source or not. Could well be, for the Aux heaters use engine fuel, so have to vent off CO2 and water vapour somewhere.

 

[jaymanek]

Erm the thing you describe is the air filter intake?? At least thats about where its located...
Jay

 

[kusanku]

If you have an Aux heater, may be that pressing whatever buttons puts you in "Aircon Off" mode will also turn the Aux. heater off as well. Certainly does so on my diesel E class.

If so, choose a cold morning & you should be able to find out if this is the source or not. Could well be, for the Aux heaters use engine fuel, so have to vent off CO2 and water vapour somewhere.

There is a separate switch to turn off the auxillary heater. I could try that next time the car decides to emit the fumes.

 

[Dieselman]

Does anybody know what this pipe is connnected to? I suspect it must something to do with the turbo, but not at all sure.

It's the exhaust for the auxillary heater. It is only used when the engine is cold.

 

[kusanku]

That's interesting. I've had the fumes mainly when the engine is hot, so sounds like something is amiss in relation to this.