Fumes inside the cabin

[popalock]

I've a W203 C class diesel estate and pungent engine fumes (not raw diesel) are noticeable inside the cabin. Now, I know you might say this is an interior issue, but I'm convinced the problem lies in the engine (as the smell is noticeable when I'm outside, standing next to the bonnet or ESP when I open the bonnet), which is why I'm posting here.

Another similar fumes post seems to conclude with the idea that the injector seals need changing. Just wanted to canvas thoughts

other points of note are

- the bonnet rubber seals aren't a perfect fit (see below image). you can see a build up of either dirt or fumes where the seal is not a tight fit
- the exhaust smells clear
- the fuel pipes are dry
- I had the car recently serviced at an inde MB garage highly recommended on this forum (shock, horror I know). I mentioned the issue to them, and they said it was the fuel pipes, had them changed, and I've still got the same issue. So not going back there again

 

[Auto-mobile]

injector seals or the exhaust seal between the turbo/cat.

 

[GordonTarling]

Remove the engine cover, then start the engine. Almost certainly a blowing injector seal.

 

[Troon]

The rubber seals are for noise insulation. There should be no fumes in the engine bay anyway - the cabin air intake is under there!

+1 for the injector seals: get that cover off and see.

 

[popalock]

thanks all.
ok will take a look - keep in mind the fumes only become odour obvious once the engine is properly hot... not sure if this changes anything?

So where do I look and how do I know if the seals are leaking? What am I supposed to look out for?

thanks!

 

[mersum1es]

Foot of the injector is moist or black, or there could be lot of 'tar' if leak has been developed long time. You also may hear and feel puffing sound when air blowing by the injector.

 

[popalock]

@mersum1es - thanks for the tips in identifying. I couldn't see anything obvious, and definitely could feel any puffing sounds. HOWEVER I could hear a constant hissing noise when I had my head close to the part of the engine highlighted below. Assuming this is an injector? the fumes are not major in anycase, but the smell was more noticeable in this area. Rest of the engine is clean, grease free, and no hiss. Except for this bit. Conclusions?

 

[renault12ts]

No..that's not an injector. The injectors are that array of things on the top of the engine all connected to each other by a pipe.

 

[popalock]

*could NOT feel any puffing..

No..that's not an injector. The injectors are that array of things on the top of the engine all connected to each other by a pipe.

ahh thought so. but that "thing" Ive highlighted is connected to them so thought it is related somehow. The injectors looked clean and were silent. The "thing" was hissing slightly + the region around it was oily so thought that might be the culprit.

I have the stress the fumes are not powerful, but are strong enough to make you not turn on the ventilation inside the cabin. When opening the bonnet after the car gets nice & hot it hits you fairly obviously

 

[sspeed]

I have arrowed the injectors on the C270 Cdi..
Look at the base of the injectors.. Where they meet the engine..
I haven't got a photo that looks down into the area but you will see what to do from this photo..

Look / listen closely with engine on tickover. Warm up the engine if you have to...
You may see a leak of black tar / fuel / soot and maybe hear a sort of chuffing sound. (That is escaping exhaust gasses from the injector seal).

Just found the last 2 photos on the web..
Hopefully yours wont look like these !!

 

[mersum1es]

High pressure pump (part in you pictures) may be noisy and producing kind of hissing noise. However your pic look like there is a slight leak somewhere because the pump is moist. But that would diesel, not exhaust fumes.

Like Simon above said injectors are the one which should be checked, even small hint of moist or black stuff is pointing starting bypass leak. If all dry and ok, check exhaust/intake manifold/turbo seals/fittings.

 

[popalock]

ok double checked. Fuel injectors look fine, dry and clean

triple checked the pipes, and this time on the part covered with gauze material/fabric, I noticed fresh diesel leaking through.. I purely visually inspected them last time. When I say I got them changed, I actually only got one changed that was obviously leaking at the end. but the rest stayed put

maybe my sense of smell isn't perfect and it is diesel I'm smelling - it just doesn't smell like diesel you've spilt. Anyway, so will need to have the high pressure pump checked, get the pipes changed, and ensuring the bonnet sealing is a tight fit.

do I need to go to an MB specialist for this, or can any local garage handle it?

 

[Benza750]

Get a specialist to check it out.

If its been leaking diesel you will need to get the coolant hoses & v belt checked to make sure it has not affected them.

The bonnet sealing wil not matter as already pointed out the air intake is above the battery on the passenger side of the engine bay, you will always get the smell in the car if there is a problem in the engine bay unless you have the A/C set to re circulation so the air intake is shut off!

 

[popalock]

MB specialist OR diesel engine/fuel injection specialist? Want to avoid having to pay for a new high pressure pump (diesel specialist can normally repair these right?)

 

[sspeed]

YES the high pressure pump can be rebuilt with new seals..
Bosch actually sell a repair kit for this..
I would go to a Diesel injection specialist and ask if he will rebuild your pump with new seals.. Ask how much..

There are one or two people (on the other forum I think) who have done this job themselves..

I suspect if you went to Mercedes then you would end up paying for a new pump.

PS I have just found the how to on the other side..

http://forums.mercedesclub.org.uk/showthread.php?t=113039

Good luck.

 

[mersum1es]

Some story from this side too:
http://www.mbclub.co.uk/forums/engine/136662-e320-cdi-fueling-problem-3.html

 

[popalock]

quick update - garage/diesel specialist changed ALL the fuel pipes this time and most of the smell leaking into the cabin has gone. The high pressure pump was ok, it was the pipe going into it that was leaking apparently. The pumps run at a higher pressure and thus the pipes were more susceptible to leaking.

Interestingly they + another specialist told me these more modern pumps weren't really repairable as the leaks would often just reappear somewhere else on the unit even after new seals etc..

I wonder how clear should a hot engine smell? Maybe it needs a thorough clean or even a detailing

 

[didi w203]

Yep thorough clean me finks..get some bubble gum spray by Autosmart. Its lush, spray inside car and you will want to eat the air lol. Other flavours available too...try ebay.