W124 250 diesel leak after pull start

[EireJames]

Well chaps, I think I may be after damaging her :Oops:

Left work today at 6.30 ish, ran out of diesel on the way out (my fault, she was low on it). Strolled down to the petrol station (few hundred yards), they didn't have gallon drums, tut tut. Rang a chap I work with, he kindly arrived promptly with a gallon of diesel for me but the Merc was airlocked as I feared. Rang the recovery dudes (free breakdown with insurance), he arrived and put her on the flatbed and off we went to the garage again, she still wouldn't start so he towed it around the forecoart, started promptly enough.

Drove home and left her idle, steady drip of diesel from somewhere under the engine, I fear it may be the fuel pump.

 

[brianbrian]

Take the airbox of and you can see where it is leaking from , you may have the luck off the Irish it could just be a fuel hose. Hope this helps

 

[M.G.]

Hi EJ,

Sorry to here your woes -

Although you may be lucky and only have a simple leaky pipe / hose etc

A common one is the leak-off hoses -
They link the injectors together in a sort of daisy chain affair ( these often perish over time and when they eventually let go - it makes quite a mess )
Have a look at your injectors and you will see a series of very small pipes ( hoses ) that link them altogether.
note - the first one will have a longer hose that goes back to the fuel filter assembly - and the last injector nearest the windscreen will have a short dummy pipe the is meant to be blanked off
Basically these pipes are for excess ( unused ) fuel to be returned back to the fuel tank

Another possibility is the fuel feed pipes ( rubber hoses ) IIRC located below the air filter housing at the side of the engine below the main injector pump
( on my 300D ) which I'm guessing has a similar set-up, there is a small 'pre' filter strainer with associated pipe work

As you say you can see fuel dripping down - it shouldn't take too much investigating to check the bits mentioned above

Good luck - Let us know hows you get on

Regards M.G.

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edit > I'm just too slow (at typing) :lol:

 

[ncooper]

Drove home and left her idle, steady drip of diesel from somewhere under the engine, I fear it may be the fuel pump.

Did your helpers perhaps open the bleed screw at some point and not tighten it up when the engine started?

Regards,
Nick

 

[EireJames]

Will have a look at those bits gents, many thanks. I had replaced all those little hoses when I first got the car to they aren't perished anyway. Will try and get out of work early and utilise the daylight later

No bleed screw as far as I know on the 250 diesel.

 

[EireJames]

Well had a looksee after work, no leaking hoses anywhere, removed the filter box and saw where the little drip originates from........

from the connection on the extreme right, just below the knurled threaded bit, close up

I wonder was it leaking a while and I only noticed when she was on the drive idling, seems not as bad today though.

Thanks for the suggestions too

 

[roadhog]

Have a look here .

 

[Number_Cruncher]

I would urge caution before beginning to replace delivery valve seals. It's very easy to make a mess of the job, an expensive mess!

You need to clean, clean, and clean again before opening the pump up - the slightest speck of dirt in there, and you'll ruin that pumping element. Consider carefully where you will do the job, and cover anything which might shed debris into the open pump. Needless to say, use a clean pair of latex / nitrile gloves.

Fit a new copper crush washer as well as the O ring.

Don't disturb or dislodge (however slightly) anything lower down than the copper washer AT ALL - use a small pick to get the copper washer out.

It's best if you use the correct splined socket, which you might be able to obtain from MB.

 

[EireJames]

Thanks for that lads, being honest I don't intend fixing it, the car is for sale at the mo, little interest in it, very few serious callers. I will just make anyone who sees it aware of the issue. It's only one of the valves is leaking.