fuel leak

Discussion in 'Engine' started by ricardo62, Apr 19, 2014.

  1. ricardo62

    ricardo62 Hardcore MB Enthusiast

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    Hi as per my previous posts I think I have found out the problem why my diesel e 320 was hard to start and kept cutting out.
    I noticed today a very small drip of diesel coming from underneath the engine , the thing is my 1st port of call was to take the plastic cover that is over all the fuel pies on the engine and have a look 4 the obvious leak , the thing is I could not find any trace of a leak from the pipes that I could see visible to me , im just wondering what could the poss cause of the leak be , if not from the pipes I could see then whats the next poss place it could be coming from any suggestions .
     
  2. OP
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    ricardo62

    ricardo62 Hardcore MB Enthusiast

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    Update , I went out this morning and it started 1st time , and on closer inspection have seen a small intermittent drip of diesel , its coming from somewhere under the top front of the black engine cover , not the grey coloured 1 that covers the fuel filter and pipes , , unfortunately that's as far as I got to inspecting as until I can get to my garage and borrow a special tool to undo the 6 star shaped nuts that hold it in place I cant take the cover off!
    I know this is not giving much info but I wonder if an y of you chaps can poss hazard a guess as to the poss cause of the leak , ie what might be the component under where I have described , front of engine at top to the left of the oil filter if you stand facing the car ?
     
  3. mersum1es

    mersum1es Hardcore MB Enthusiast

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    There is a high pressure pump in the front of the engine. If your car is W210 there is also transfer pump. W210 system o-rings of the fuel hoses are prone to fail (try search 'fuel o-rings'). Also hoses themselves may brittle. Then sometimes hp-pump leaks too, seal kits are available: High Pressure Diesel Injector Pump Seal Replacement - Mercedes-Benz Owners' Forums

    W211 has different fuel system, where o-ring are not big problem, then it's most likely hp-pump or fuel quantity valve.
     
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    ricardo62

    ricardo62 Hardcore MB Enthusiast

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    thank you for replying quickly , yes I have just been doing some research and it looks like leaky o rings are the poss cause , ,I guess as I am no mechanic , that it will be a trip to my garage to have it fixed
     
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    ricardo62

    ricardo62 Hardcore MB Enthusiast

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    I apologise for keeping posting but I have a further question , it is only a small drip at the mom , but until I get it looked at , once its running it seems fine , so can I assume that it will keep running once I start it , or will this leak cause it to break down
     
  6. mersum1es

    mersum1es Hardcore MB Enthusiast

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    Usually low pressure leak causes just starting problem or humping idle. And ofter starting will be harder and harder... If it's hp-pump, sometimes leak will actually decrease when system is warming up. If the fuel pressure is not possible to maintain at full throttle, result is limp mode or engine cut out. One problem is that you'll most likely soak your poly v-belt with diesel, and at some point it will jump or break.
     
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    ricardo62

    ricardo62 Hardcore MB Enthusiast

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    thanks luckily as far as I can tell the polybelt is dry with no diesel on it, also no warning lights on dash and drives normaly once its warm .. so I assume its the lp side then
     
  8. OP
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    ricardo62

    ricardo62 Hardcore MB Enthusiast

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    took cover off engine earlier and had a good look , it seems to be a slow drip coming from back of the pump , it is not dripping onto the polybelt luckily , alldry .
    its hard to tell with leaks because where they look like there coming from is not neccesarily the case as fuel migrates , but I cant see any obvious leaks from the pipes or where they enter the pump housing , so it looks like back of pump where it seals against engine , is this a common leak spot ?
     
  9. Dieselman

    Dieselman Banned

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    Yes. There is a seal kit available.
     
  10. OP
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    ricardo62

    ricardo62 Hardcore MB Enthusiast

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    thank you , im no good at mechanics so I guess it will be a trip to my garage to have it fixed , it looks like a fairly time consuming job , radiator off etc , so I guess it wont be cheap if that is the problem .
     
  11. mersum1es

    mersum1es Hardcore MB Enthusiast

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    I would start with new low pressure pipes and o-rings. Often they do leak where they go inside the hp-pump, and it seems like pump is leaking. Low pressure pipe change is relatively fast, and if it is the pump itself, it's not big job to remove them again. Just ask your mechanic to prepare that pump need new seal kit.
     
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