E320cdi exhaust fume smell in car

[Jonny2tanx]

I think I am getting exhaust fumes into the interior of my E320cdi estate - I sometimes get stingy eyes and a taste in my mouth that I think is exhaust fumes. There doesnt appear to be any leaks on the exhaust system though, so I am puzzled. I left all the vents closed this morning and it appeared to be better, but appeared to start coming through again when I opened them back up.

In addition, the fuel consumption seems to be a bit higher than it used to be -now getting high 20's on my daily commute instead of low to mid 30's that I used to get. The car has recently had the gearbox rebuilt, so could that have anything to do with it? Is the exhaust disturbed when removing the auto box? I have also noticed a gentle ticking noise when the car is being driven, but I cannot hear it when it's idling or being revved out of gear - it only appears to be when under load. Could all this be linked? Any suggestions where to start looking would be appreciated.

 

[panason1c]

Check the seal between the exhaust manifold and the downpipe, the clamp may be broken allowing exhaust fumes to accumulate under the bonnet and creep through the bulkhead into the passenger area.

 

[OlafMaxwell]

The ticking is normal, nothing to worry about.

A thought is to take the car for a high speed drive, 70-80mph, see if there is wind noise. Most likely place for exhaust fumes is through bad rear door seal though the exhaust probably comes off to get at the transmission. If a leak at manifold the fumes could get to the air intake and into the car.

 

[panason1c]

Check the seal between the exhaust manifold and the downpipe, the clamp may be broken allowing exhaust fumes to accumulate under the bonnet and creep through the bulkhead into the passenger area.

When the gearbox was removed the engine would have been tilted downwards, this is likely to have broken the seal between the manifold and the exhaust downpipe.

If you open the bonnet and have someone floor the accelerator whilst you watch the area where the downpipe joins the turbo you will probably see a puff of smoke leaking out from the joint if it is leaking.

Let us know the result.

 

[Jonny2tanx]

I've crawled all over and under the car as far as I can without a hoist while my girlfriend has been revving the engine. No sign of any puffs of smoke anywhere that I can see. I'm pretty sure the smell is coming in through the air intake rather than being drawn in from outside through a bad seal or missing grommet - I've had the system on re-circulate from cold and it seems to be much better, but re-appears when I swith re-circ off. I reckon there must be a leak somewhere in the exhaust system under the bonnet, but can I find it? Not a chance. Any other suggestions?, cos I am stumped

 

[panason1c]

You might try plugging the end of the exhaust tailpipe with a rag whilst engine is at idle.....you then should hear where the exhaust is leaking as the pressure builds up in the system.........

 

[Jonny2tanx]

Tried plugging the exhaust, and the leak appears to be from somewhere around the turbo - there's a definite hiss of escaping gas but I cannot determine where from exactly. It appears to be coming from above the turbo though I cannot feel any pressure of gas on my hand at that location. Having said that, there's not much room to feel around, especially when you have fingers like mini bananas and there's a hot turbo waiting to punish clumsiness. I guess really the air cleaner needs to come off to get a better look, but will the car run without the air cleaner, seeing as the air mass gubbins is in it? There's not much room to simply move the air cleaner to the side.

 

[panason1c]

Tried plugging the exhaust, and the leak appears to be from somewhere around the turbo - there's a definite hiss of escaping gas but I cannot determine where from exactly. It appears to be coming from above the turbo though I cannot feel any pressure of gas on my hand at that location. Having said that, there's not much room to feel around, especially when you have fingers like mini bananas and there's a hot turbo waiting to punish clumsiness. I guess really the air cleaner needs to come off to get a better look, but will the car run without the air cleaner, seeing as the air mass gubbins is in it? There's not much room to simply move the air cleaner to the side.

Exhaust clamp!...(or at least the seal broken)........probably broken when the engine was tilted during 'box removal.
I would expect the engine to idle ok without the airbox though you should see evidence of any blowing by soot in the area.
I would take it back to the garage and let them sort it now that you can point them in the right direction.

 

[Jonny2tanx]

I released the mounts and moved the air cleaner box to the side for a look and all I could see was a slight hint of soot on the joint between the turbo and the catalytic converter, so I guess thats where the fault lies. The underside of the heat shield is also pretty black with soot, so it's all pointing in that direction. It's booked in at the garage on Wednesday to be fixed (hopefully) - good thing too, as it is getting worse and my lips are now tingling. As I said earlier, the fuel consumption has also got worse since I noticed the smell. Is a leak at this joint likely to be the cause of this too?

 

[Jonny2tanx]

Well the garage had the car all day, and tried to fix the leak, which they confirm appears to be between the turbo and the cat, 'without having to replace any parts'. They failed!!! They now tell me that they need to remove the exhaust manifold and the turbo to reseal everything, and also tell me they will need the car for 1 1/2 days. I can't see any reason whatsoever why they would need to remove the turbo, with the possible risk of damage when they do it, to reseat the seal between the turbo and the cat. Am I missing something here, or are they trying to take the mick?

I can understand that the fit on these parts appears to be a bit tight, but would have thought that it would have been easier to remove the exhaust to fit a new seal, and rebuild it backwards, rather than to remove the manifold. Am wondering if they think the fumes have addled my brain

 

[tech lee]

hi jonny, i wonder if this can help. i repaired a car this morning as the customer was complaining of a fuel/exhaust smell in their c class. when checking the car i found the injector seals begining to leak. this would explain the ticking noise and the smell nipping your eyes. the thing is once the engine is hot the injectors usually seal themself. it's not expensive for the washers and replace the bolts while you've got them out, the only thing to watch out for is the bolt holes require cleaned out before you refit them. use a 4.5 mm drill bit by hand, this usually does the trick.

 

[psmart]

Picture this in your lungs....

...pictures of a Turbo to Primary Exhaust Catalyst, where the clamp has broken and carbon has coated everything in the engine bay.....

 

[psmart]

Pictures of airfilter after the seal had broken...

..not on the air inlet side, that the filter fingers are all carboned up. On the air MAF/Turbo side, its clean.... airfilter did its job, but if this crap is getting into your cockpit, wont be good at all

 

[Jonny2tanx]

Hi psmart

I can confirm that it was the turbo to cat seal that was at fault, as I suspected. Am just glad I didnt let the first garage I took it to dismantle the manifold and turbo, where they thought the leak was, and with them telling me that often the turbo gets damaged when they dismantle the joint, and that the bill could be quite hefty. (Somehow I dont think I will be using that garage again, which is a pity as they were handy for where I work.) I have now got a new seal and clamp and a fume free car.