smell of petrol coming through ventilators

Discussion in 'Engine' started by mattc, Oct 22, 2008.

  1. mattc

    mattc Hardcore MB Enthusiast

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    The fuel tank on the 124 estate had a small hole on the filler neck. this is have 'repaired' with glass fibre and resin..we will see how long it holds. Naturally with this leak there was a smell of petrol around the car whilst stationary outside the house. this has now gone but has highlighted another problem. I am smelling fuel coming through the middle front vents so am guessing something is loose or split up front.

    Any suggestions where to look first (and a nice picture would be good too as I am hopeless with a simple written description:eek: )

    matt
     
  2. st13phil

    st13phil MB Club Veteran

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    Where the flames are coming from? :D (sorry, couldn't resist :eek: )

    On a more practical note... a smell of petrol coming in through the vents would suggest that the most likely source is under the bonnet so you're going to have to look for dampness around any pipe unions, joints etc. The problem with tracing minor petrol leaks is that the stuff evaporates pretty quickly and once you've run the engine the warmth speeds the evaporation further. Also, petrol is quite a strong aromatic so it can sometimes be difficult to pinpoint where the strongest smell is, but that's what you're going to have to do.

    Whatever happens, don't ignore it. Petrol fires are no fun at all.
     
  3. m1bnk

    m1bnk Member

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    Often much easier to spot with the engine running because the fuel system has some pressure. Better to try and find it with it off first, poking around a running engine's never a good idea.

    Petrol does stain things though, so starting from the firewall follow the fuel lines through the engine compartment and look for staining around unions. If all else fails I got a nice trick from a friend - tape newspaper to a big sheet of cardboard and put it under the engine compartment - run the engine for ten minutes. If the leak is bad enough to give a drip then there'll be a stain where it's dissolved the ink on the newspaper. The leak will be above the stain, or at least the drip point is and you can follow it up to the leaking union.
     
  4. Brian WH

    Brian WH MB Club Veteran

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    One thing is certain - The leak will be in a place you cannot see or get at.:devil:

    Don't play with FIRE, get it seen to quickly and by someone who knows where to look and what to do, before you have to call the fire-brigade, or worse, when it goes up in flames.:crazy: :crazy:
     
  5. OP
    OP
    mattc

    mattc Hardcore MB Enthusiast

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    thanks guys - will try and find it tomorrow. anyone go a picture showing path of fuel line from tank to engine?
     
  6. OP
    OP
    mattc

    mattc Hardcore MB Enthusiast

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    ok. so have had a good poke around and cannot see anything. The estate has one of those charcoal evaporation filters. Pretty certain it has never been changed - would it make that much difference smell wise or am I barking up the wrong tree (though I am going to get a new one anyway)
     
  7. jaymanek

    jaymanek Authorised Forum Sponsor Authorised Forum Sponsor

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    not had much experience with them, but I imagine if they were to go rusty and leak, the vapour would smell somewhat..
     
  8. OP
    OP
    mattc

    mattc Hardcore MB Enthusiast

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    Update

    Took the front wing liners off (gave everything a good clean - half a field of mud fell out of the passenger side:eek: ) and disconnected the charcoal filter. very small rust hole at the bottom and absolutely no smell of petrol from it :mad: . Really am beginning to think I am missing something. Does anyone have a diagram of all the fuel lines and where the connection are? I have looked on the russian site but am not finding it too helpful.

    your all confused, matt
     
  9. andy_k

    andy_k MB Club Veteran

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    Is the car over fuelling and what you are smelling is unburned rather than leaked fuel?

    I'd check air filter, cam breathers and plugs to see if any of those give you a hint
     
  10. OP
    OP
    mattc

    mattc Hardcore MB Enthusiast

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    Not sure! Smell can linger even if car has not been run for a while.

    Air filter was changed about 10K ago. Plugs i will look at. How do i check the cam breathers?
     
  11. poisas

    poisas Hardcore MB Enthusiast

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    heh, i had something the same : fuel smell was coming from the middle vents inside in peugeot 406, but the smell was like only as engine was cold, i was trying to find the leak, but could see anything, and you have to notice, that there is no mark left, because fuel is dissapearing like evaporating, and one cold morinng i opened engine hood and started the car, and if i can smell the fuel inside the salon from the vents, so the leak must be somewhere close salon air filter, so at first i saw nothing, than i tried to push some rpm's and ualia, it was a tiny miny small pssssing of fuel in one joint pissing some 20cm from the pipe in the return to the fuel tank pipe, , i have removed it, cleaned and tighted back, and it was ok, but you have to know, that this is very dangerous, i had lots of chances to have fire under hud,
    so my suggestions : look somewhere close to the salons air filter, thats why you feel the smell inside.
     
  12. OP
    OP
    mattc

    mattc Hardcore MB Enthusiast

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    Latest update. Found petrol drip,drip,dripping over the diff yesterday. Got it on the stands today and started engine. Fine mist of petrol coming from the pipe above the diff. This pipe comes from the fuel pump right next to the petrol tank (Haynes calls it a pump but how can that be when there is no wiring to it!? - confuses me anyway). This pipe leads to the fuel filter protected by the undertray (which is where i think the real fuel pump it next to the filter!)

    So now I need a new pipe - look on the Russian site on a 280 estate, go into the fuel system section 47; within that section I look at no. 45 fuel lines and the line i believe i need is not numbered. It is the almost horizontal fuel line between numbers 68 and 71 on the diagram. Can anyone tell me that part number so I can order it tomoorow please.

    Sorry I dont know how to "capture" the picture and then label it:eek:

    I hope this will cure my problems though I do question how the smell is getting forward to come through the front vents whilst travelling at speed:eek: . Still; guess it is a case of isolating one problem at a time.

    thanks in advance,

    matt
     
  13. OP
    OP
    mattc

    mattc Hardcore MB Enthusiast

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    Ha. Think I have found it. A124 470 2875 - £41 on the inchcape site. Seems mighty expensive for a hose - can I buy a non pattern part for this?
     
  14. Ian B Walker

    Ian B Walker MB Club Veteran

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    Your lucky day Matt. Just breaking an estate and the hoses on it are good. Just got your text and replied to it.
     
  15. kth286

    kth286 Hardcore MB Enthusiast

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    The hose that normally leaks is from the filter (hidden by the cover) to the metal pipe above the rear subframe, and then that metal pipe goes to the engine compartment and is the fuel feed.

    You should not fit a secondhand petrol hose.

    The hose is sold by the metre and is approx £14 per metre but you will only use part of that, perhaps half (I cannot remember).

    I have part number A230 476 87 26 listed but not sure if latest number.

    You will need to give your VIN to parts person at Merc dealer counter, they normally keep it in stock.

    The new hose clips are part number N916033 011100 cost £1.29 each.
    (2 required and are fitted with screwdriver).
     
  16. andy_k

    andy_k MB Club Veteran

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    may be preaching to the converted but do use the proper clips and don't try to save a couple of quid by using jubilee clips
     
  17. kth286

    kth286 Hardcore MB Enthusiast

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    Those are the proper Merc clips as specified in EPC for fitting this fuel hose.
     
  18. OP
    OP
    mattc

    mattc Hardcore MB Enthusiast

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    Seeing as I am technically inept at capturing pictures from the Russian site (or any for that matter:eek: ) could you post a picture of the bits you mean? I ask this as I dont see the cliips you are refering to in the Russian site.
     
  19. OP
    OP
    mattc

    mattc Hardcore MB Enthusiast

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    And is that clip used all over the fuel line system. If it is I might get a few more for mine at the same time and replace them all.
     
  20. kth286

    kth286 Hardcore MB Enthusiast

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    Matt

    Use the Russian site as a guide only, as it does not keep up to date with Merc part number changes.

    As you can see from the part number above, the fuel hose is an SL part number now.

    Whilst we have the same, cars I do not know off the top of my head when the switch to single fuel pump was (and therefore our different pump and filter layout to the previous models).

    The Russian site does not do a good job of showing the pipe you need.

    The Merc EPC system breaks it down to the individual pump and filter layout specifically applicable to your own chassis number.

    Therefore your best bet is ALWAYS deal with main dealer and give your VIN.

    If you have not done so you may want to take the cover off the pump and filter first before contacting the dealer, then you can see for yourself. They are 10mm nuts and yuo will need a slim extension and socket as some are deeply recessed.
     

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