mystery feint smell

[Darragh1]

Hi again,
I am having trouble identifying and locating the smell. I sometimes get it in the morning when I open the tailgate before cold startas if it has built up over night. It emanates from the passenger seat area underneath the car. There is no loss of coolant, no oil or fuel leaks and the under body is dry, checked by my mb specialist. The smell arrives into the cabin while driving slow or fast or when stopped like a waft, an emission (regardless of aircon on or off) and I find it hard to identify. There are no fault warning lights. I have used engine cleaner and hosed down the left side in case of any of residual smells from the car's history.
I wonder if it might be an intermittent waft of exhaust.
It has a subtle whiff of diesel mixed with a tincture bad socks.
This is probably a needle in a stack of needles but by any chance does this ring a bell for anyone?
S212 E250 OM651 204bhpm 2010 with 120000+ miles
Thankliest regurgitations,
D

 

[StMarks]

​

It has a subtle whiff of diesel mixed with a tincture bad socks.

Is the OM651 engine susceptible to the "Black death" injector leakage that blights some Mercedes engines.? Fwiw the scent description sounds reminiscent of mine when I first got it, and before I had my injector seals replaced.

"feint smell" -that would be Ether or Chloroform

 

[Petrol Pete]

Hope its not 'the black death'

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Accept third party cookies

 

[DSM10000]

I was thinking Magic Mushrooms......

 

[E55BOF]

"feint smell" -that would be Ether or Chloroform

No, that would be a faint smell, and also what the OP has. It would only be a feint smell if the real smell came from somewhere else...

 

[StMarks]

No, that would be a faint smell, and also what the OP has. It would only be a feint smell if the real smell came from somewhere else...

Lol, well corrected E55BOF. Consider me well & truly told mate.!

 

[E55BOF]

In Pedants Corner here... Sad, innit!

 

[StMarks]

Sad, innit!

Imho; No, it is certainly not "sad" mate.
To have knowledge that is correct, the courage to expound it, and the integrity to do so in a balanced and courteous manner is something to be proud of.
It seems a sad inditement of our society, that the ignorant & bigoted should be empowered to shame our betters with such sleights.

 

[Harrythedog]

Could be the rear washer feed pipe, that runs inside the car and is prone to disconnect

 

[Darragh1]

I had the broken washer hose at the tailgate hinge and I fixed it. That is not leaking.
Three of four injectors were replaced before I bought the car. Also the seals were all replaced with the timing chain job I had done. The injector area is dry.
It might not be magic mushrooms and might be described as deceptive and evasive.
I took off the plastic engine cover and washed and dried the fabric pad of historical residuel oil/diesel but i still get a smear of black oil or diesel on the top of the wiring block casing (see photo attached of an om651 not mine black scribbles.) I think i might take off the pad to see if the smell could be emanating from the pad when hot.
I appreciate all comments, any other suggestions?
Thanks
D.

 

[Darragh1]

Hi again,
I think i have dispelled the notion of residual odours wafting from the old padding under the engine cover...
I took off the plastic engine cover and drove the car a bit. Next morning there was the same rising smell . No evidence of any oil or diesel coming from the injector area. The smell doesn't emanate from the engine bay anyway, it creeps or wafts into the cabin intermittently and evident when i open the tailgate in the morning or from the under body in the passenger seat area.
When Diesel and Old Hurling Sock met, It was Moirdui.

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Accept third party cookies

I wonder what Mr H would do? I mean, he was a self made millionaire and Mrs. H was indeed goijeus, they probably would have ridden down in the sl to the main dealer and splashed out a few bucks to get to the root of the odour issue. No, they would instead have sent Max who knew a guy who knew a guy who fixes automobiles and then while it was being fixed he might nip home in the courtesy car to fix mr and mrs H's favourite dinner. There would be no fannying about on mercedes fora. There wasn't even internet.
I hope I have made myself unclear,
D.

 

[Darragh1]

So today I checked the coolant level on a cold engine and it is down 2cms. Since my new water pump and thermostat three months ago I presumed the system would remain sealed. I have replaced the two hoses on the top of the radiator and another small hose was replaced by my indie. No need for expletives but ffs. The fuel filter housing looks dry. The back of the engine into the fake bulkhead looks dry.
I wonder if this smell which comes and goes could be coolant dripping onto somewhere there is residual diesel from old leaks and this combines to become this all too familiar diesel and socks melange? This is a 120000+ miler and I know its plastic components are brittle but the inability of the car to contain its coolant is pathetic.
I will wear the path to my mb indie again but is there anything else for me to check visually before I do so?
thanks
D.

 

[Darragh1]

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Accept third party cookies

 

[Phil1968]

I recognise the description of the smell you're referring to, on my previous Vito van (with pretty much the same engine) it was an injector starting to fail.

 

[StMarks]

Probably not going to help, but fwiw..: Last year a friend of mine (with a Toyota) had a persistent coolant leak that he was unable to locate.
He had everything they could think of checked or replaced, even had the cylinder head off at one stage !
Nothing found, no drips or puddles from the engine (he even hired a garage near his work for a month, so he could park it in a dry environment to check at that end of his daily commute as well as at home).
Still the coolant level would gradually drop.
Long story short( ^that's very abbreviated ! ) it transpired that it was a tiny fracture in the transfer pipe to the heater matrix. The leak was so slight that the cabin warmth presumably evaporated the liquid before it accumulated enough to be detectably "damp", and it's location (behind the engine bulkhead, but in front of the heater matrix) meant that replacing it was "rather involved"

I would finish with "Hth", but I rather suspect that you'll hope that doesn't help at all.

 

[Darragh1]

Phil1968,
No evidence of leaking injectors or 'blow-by' so far. Injector seals were done when I got the timing chain replaced. Also three of the four injectors were replaced by the previous owner and the 4th seems good.
Thank you for the reply,
D.

 

[Darragh1]

StMarks,
Hopefully not dash out heater matrix related. It wafts whether the aircon is on or off, if that is relevant.
Thanks for the reply,
D.

 

[Darragh1]

So I have found a coolant leak. There is a hose at the back of the engine which goes through that false bulkhead and beyond that into what I presume leads into the heater matrix. Where it enters the matrix there is evidence of coolant which is bleeding down the left side of the engine and so probably down to where it smells under the car at the passenger seat. I'll put up photos tomorrow.
Engine out or dash out or some negotiating in the space in between I wonder.,,,
Thanks for reading folks,
D.

 

[MrGreedy]

Could it be two issues? Just thinking about the work you light have to do. Could there also be a slight gasket leak on the top of the fuel tank? (noting you smell something when opening the tailgate).

On some cars, the top of the fuel tank is visible and the pump etc easily accessible be removing the rear bench. Might be work removing it and having a sniff regarding the diesel smell? Quick and cheap DIY anyway.

 

[Darragh1]

Could it be two issues? Just thinking about the work you light have to do. Could there also be a slight gasket leak on the top of the fuel tank? (noting you smell something when opening the tailgate).

On some cars, the top of the fuel tank is visible and the pump etc easily accessible be removing the rear bench. Might be work removing it and having a sniff regarding the diesel smell? Quick and cheap DIY anyway

I have had the rear bench off several times and never noticed a smell but I will pop it off again just in case , take off that rubber cover and inhale. thanks

I need proper lighting to show the coolant leak at the bulkhead will put up photos as soon as i can