W124 E300d Fuel Lines

[SilverSaloon]

Hi

I have a minor fuel leak on my clear plastic pipes (ones that go to/from the fuel filter).

I have replaced the 3 O-rings at the fuel filter and 1 at the pre-filter easily with VITON seals. This fixed the fuel leak at this end (which was squirting around the engine bay at one point!! eek!)

I still however have a leak at the other end of these clear pipes. This seems to be causing me a cold start issue. When the car is left standing the fuel that goes from the fuel filter leaks out so there is no fuel in the pipe in the morning, making starting a big problem. Car starts for 3 seconds fine, but then cuts out - i assume it uses the fuel in the filter and then there is no fuel in the pipe so it cuts out. i then have to crank for ages to get it to start.

When running there are small air bubbles in the pipe aswell.

Basically i am hoping that replacing these bottom O-rings will sort the issue. Problem is they seem hard to get to.

I seem to be able to access one of them (i think the only one that actually is leaking) from underneath the car when i remove the metal engine shield.

what i need to know is how to remove it - it seems there is some sort of clip on it... is it just a case of pulling the clip off and then pulling the pipe off? as its hard to access i dont want to break anything...

i want to avoid removing the manifold as i dont have time to do that at the moment but i'm stuck with the cold-start problem. so need to atleast fix this one seal in the hope it will cure the cold start issue and then i can remove the manifold when i have more time.

i also need to check the fuse in my OVP relay, but i know the fuel leak is there so this is my 1st point of call.

does anyone have a diagram or can tell me how the lower pipe is connected? i think its the one that goes from the engine to the fuel filter. on the battery-side of the engine bay.

its the lower plugs of the end of the red pipes in the following diagram i need help on how to disconnect:

thanks in advance!!

 

[Dave Lewis]

To release the pipe, you press the clip inwards, and pull the pipe off. I would advise replacing all the plastic pipes, not just the o-rings, as the pipes get hard and brittle with age, and cause difficulty with sealing the o-ring. The pipes are not expensive from MB, and come complete with clips and o-rings. About £35 for the lot, if I recall correctly.

 

[SilverSaloon]

To release the pipe, you press the clip inwards, and pull the pipe off. I would advise replacing all the plastic pipes, not just the o-rings, as the pipes get hard and brittle with age, and cause difficulty with sealing the o-ring. The pipes are not expensive from MB, and come complete with clips and o-rings. About £35 for the lot, if I recall correctly.

hi

thanks - is this on a W124 as from looking at the other threads, the white horseshoe connections are different between 124 and 210 models.

i have 1 pipe already, so will probably replace the pipes aswell, but just the o-ring for now as i guess to replace all the manifold has to come off for access??

also whats the best way to remove these? from under the engine bay or from above? i heard that better access is made by removing the washer bottle?

 

[Dave Lewis]

Yes, I had a '95 W124 E300D, OM606, with the horseshoe connectors. Removing the washer bottle helps. I think I took the wheel off and did it from underneath. One of the red pipes on your diagram is the main feed to the filter, the other one a return. Air bubbles in the feed pipe is bad news, and will cause the starting problems. It is worth taking the manifold off anyway, as it would benefit from being de-gunked of residue from the EGR. Parrot of Doom did a 'how to' on this I think, for a W210, but it's the same deal on a W124.

 

[SilverSaloon]

Yes, I had a '95 W124 E300D, OM606, with the horseshoe connectors. Removing the washer bottle helps. I think I took the wheel off and did it from underneath. One of the red pipes on your diagram is the main feed to the filter, the other one a return. Air bubbles in the feed pipe is bad news, and will cause the starting problems. It is worth taking the manifold off anyway, as it would benefit from being de-gunked of residue from the EGR. Parrot of Doom did a 'how to' on this I think, for a W210, but it's the same deal on a W124.

thanks - i do plan on doing the manifold & egr stuff but havnt got the time to do that job yet, but do need to be able to start the car easier - its a nightmare at the moment

 

[SilverSaloon]

...

 

[television]

The return to tank often gets over looked,,the air will alway rise to the highest point


http://www.detali.ru/cat/oem_mb2.as...GM=717.433&CT=F&cat=15S&SID=47&SGR=045&SGN=03

http://www.detali.ru/cat/oem_mb2.as...GM=717.433&CT=F&cat=15S&SID=47&SGR=060&SGN=04

 

[bolide]

This problem generally occurs after you disturb the pipework. Most times you can fix it by replacing all the O-rings. I get them from the dealer at about 90p each

Nick Froome
www.w124.co.uk

 

[SilverSaloon]

This problem generally occurs after you disturb the pipework. Most times you can fix it by replacing all the O-rings. I get them from the dealer at about 90p each

Nick Froome
www.w124.co.uk

hi

i have a bag of 40 VITON o-rings i bought from a uk supplier - (so they wont deteriate with running on veg, which is why i think they have started to leak) - they were on their last legs anyway i think (very flat) and the veg was the last straw.

i've replaced these now and got the car started and got it warmed up - now left and lets see if it starts better tommorow. (here's hoping).

still a few more o-rings to sort though - need to hunt around. but i am hoping it was just these that caused the leak.

when i pulled off the pipe there was no fuel in them so there is definatly a leak somewhere.

 

[TonyVianoAmbiente]

Derek,

You are quite brave doing these yourself as they are very difficult to get at without removing the manifold. However, I had mine done yesterday by an independent specialist and they managed to do them from underneath. The manifold stayed on.

I asked how they managed and they said having the car on a lift was key. They could make fine adjustments to the height of the ramp to give the technicians the best possible access to the seals.

I did note that both technicians who had worked on the car were slim to the point of being thin. I am rather more rotund and wouldn't have had a hope of doing this job myself, lift or no lift!

The cost was very reasonable. They didn't need to replace the fuel lines as they said they were reasonably new, certainly not the originals.

 

[SilverSaloon]

i replaced the ones i highlighted in red (last night - tricky but i got to them from above). Removing the washer bottle helped and i pushed them back on using a long screwdriver as once the new ring was on they needed a firm push to get back on. i have already done the ones around the top by the filter.

No idea if the car will still be hard to start yet though!! will find out tonight i suppose!!

i checked the fuse in the OVP relay and it looked fine.

looks as if i would struggle to do the other end of the two pipes that run from the filter - (go to copper ring connections) as these bolt on but i will give it a go but i dont think they are actually leaking so may not bother.

i havnt changed the pipes yet - there are still airbubbles going up to the filter though.... (pipe 86 in the diagram above) which worries me slightly. not sure if its normal???

i cant really compare with my other 124 either as the pipes on that car are non-see thru for some reason. no leaks (yet) though!

derek

thanks

derek

 

[TonyVianoAmbiente]

i replaced the ones i highlighted in red (last night - tricky but i got to them from above). Removing the washer bottle helped and i pushed them back on using a long screwdriver as once the new ring was on they needed a firm push to get back on. i have already done the ones around the top by the filter.

No idea if the car will still be hard to start yet though!! will find out tonight i suppose!!

Like I said, you are a brave man! Good luck, hope it works.

I'm still leaking a bit of oil ...

 

[SilverSaloon]

Like I said, you are a brave man! Good luck, hope it works.

I'm still leaking a bit of oil ...

hi

not sure why i'm so brave - maybe i'm risking something i dont know about??? only thing i can see risky about it is not being able to get the pipe back on again afterwards because of access? it was harder then getting the pipes off as the new seal means it need to "pop" into position, one i did last night was particually hard but i tapped it in with a long screwdriver and hammer. worked a treat.

i put it outside last night (started fine) and it also started thismorning so seems good. although it hunted at idle for about 20 seconds after starting.....

i noticed an additional O-ring i could get to so i also replaced this last night and now there are no noticable air bubbles.... even though the tube i replaced to fix this was quite a distance from the bubbly one....

still got one o-ring to do that i can see *just* weeping as the engine is running.

all that leaves to do are the one that are NOT circled red:

RED CIRCLES = o-rings you can reach with manifold on

PURPLE (top of fuel filter) = not sure if there is an o-ring here (or if its the same size?)

BLUE (lower right) = can just get to this one but mine looks like a clip type (not the bolt on one like in the diagram)

GREEN (upper right) = think manifold has to come off to get to these or might be able to access from below but may be difficult as per Tony's comment above - re ramp access etc. You can see with a torch though and mine doesnt appear to be leaking so i will leave this one for now.

 

[TonyVianoAmbiente]

not sure why i'm so brave - maybe i'm risking something i dont know about???

I suppose I meant that you are braver than I am. I'm not confident enough to do this work myself.

 

[SilverSaloon]

I suppose I meant that you are braver than I am. I'm not confident enough to do this work myself.

i used to think that. i now go on the basis of; i'll have a go myself... if too hard or cant do it then i'll take it to a local garage to do.

i only generally do stuff if i have some sort of advice from other people, like this forum, or a how to/instructions off the net or in a workshop manual.

its good to know what exactly has been done and you know if its been done well or not.

an example is the gearbox oil i changed recently - many garages dont bother to drain the torque convertor. as i did the job myself i know that the filter has really been changed and the torque converter was drained and i know how much NEW oil was put back in etc etc.

 

[SilverSaloon]

small update - leak has reduced considerably... but is still there. car starts good again now (touch wood!)

i am guessing the other 2 seals i've yet to do need doingm to complete the fix.

I also notice a slight seep of fuel at the top of the fuel filter shut off valve. i didnt replace the old seals when i last changed the filter, so i guess this will fix this.

does anyone know if i should buy a new manifold gasket or not?

 

[Dave Lewis]

Manifold How-To It's a turbo, but still a 606.

 

[Number_Cruncher]

>> does anyone know if i should buy a new manifold gasket or not?

If you're going to take the manifold off, then, yes, buy a new gasket. They aren't silly money.

Also, you'll need to replace at least a couple of the rubber bungs that connect the crankcase vent system to the manifold (turbo OM606s don't have this). You'll need at least the one that you have to remove to access the accelerator cable bracket bolt.

I would also renew all the plastic clips for the diesel hard lines. These will be broken and brittle, and without them, the pipes flex, and fail via fatigue, leaking fuel all over in the process.

Also consider renewing all the injector leak off pipe, and the bung in No. 6

 

[SilverSaloon]

Hmmm, this all sounds like a big job.

i think i'm going to have to tackle this over a weekend or something.

are there any other things that would be good to do/clean/replace when the manifold is off?

so far i have:

- clean EGR system (as per the link above)
- replace the fuel o-rings
- renew all the plastic clips for the diesel hard lines
- replace gasket
- replace at least a couple of the rubber bungs that connect the crankcase vent system to the manifold
- Fuel pump delivery valve seals

cheers. i am guessing if i have the manifold off anyway, i may aswell tackle the above things aswell?

i may not do all these things (if its not broke, dont fix it!) but depending on when i do it and how confident i am i guess its worth consideration.

thanks

derek

 

[Number_Cruncher]

>> i may not do all these things

If the manifold hasn't been off for a while, you WILL break the bungs between the crankcase ventilation system and the manifold, and you do need to take at least one of them out to access one of the bolts that hold the accelerator cable bracket. They just pry out, and push back into place normally, but when the rubber goes hard, they break very easily.

The clips for the hard lines, again are just a push/click type of clip, nothing difficult. I found about half of mine had been broken, and were already loose.

The bungs and the clips are, like the manifold gasket, parts that I would like to have available to me before starting the job - I would then be confident of being able to get it all back together without needing to go and pick up more parts half way through.

Working steadily, taking the manifold off, and putting it back again is about an hour's worth of work, and is certainly not difficult.

With the manifold off, you can also see how clean the manifold runners are - they can block up with gunk, and you will also be able to see if the inlet valves are seating properly. You should see a black oily mess in the intake ports.

The parts I would leave alone, unless fuel is peeing out, are the delivery valve seals. A fair proportion of the people who have done this job have ended up with a car that runs roughly afterwards. As far as I know, there isn't a well understood reason why this is.