W203 - C220 CDI - Fuel Pump & Pipe Leaks Help

[Wully]

Big problems this morning, went out to the car bright and early, started the car and it fired up no problem however after five seconds it cut out. Tried a few more times and could tell it just wasn’t going to fire and to save the battery stopped.

This is the first it has ever failed to start (apart from seat controller drain of course)

Anyway before deciding what to do pulled out the mux and DAS and no fault codes showing however after checking actual values no pressure at the injection rail.

As I’m at the G/Friends I was in two minds what to do, pull it apart or phone the AA. Decided to have a look and see if there is anything obvious. Easy answer to that, diesel down the front of the engine, right time for the AA.

Didn't take long for them to turn up and after explaining what I’d found he set about cleaning the area around the pump and pipes and found the pipe attachment at the outgoing side of the fuel pump was leaking. No sign of damage to the o-ring or the connector but it was still passing. Anyway in the way of a temporary fix he wrapped the plastic connector in a clear PTFE type tape to seal it and after putting back together it fired up and a few cranks, obviously air taking it's time to release.

I thought this was the end of it, afraid not, a steady drip had appeared under the car and looking around the pipe entering the high pressure pump it seemed to be coming from this area. A torch highlighted exactly where it was coming from, the left hand side of the high pressure pump to the rear of where the plastic pipe connects to it.

Bottom line not going anywhere, it's getting recovered tomorrow and I’m in the process of going through part numbers etc on the EPC.

My question to those that know about these high pressure pumps, there is a repair kit available for the area where the leak is coming from. What is included in these kits?

I'm planning to replace the fuel pipes as they seem very brittle.

First Leak: - At item 137 at the upper Fuel Pump
Second Leak: - At item 164 at the Hig Pressure Pump

So hopefully the repair kit and the new pipes will solve the problem or I’m looking at a new high pressure pump.

Item 25 is the repair kit:-

 

[Dieselman]

It looks like it's just the low pressure pipes from the lift pump seals and replacement should fix it. If not all parts for the pumps are available from a Bosch diesel specialist.

 

[Wully]

Had a look through the EPC and called MB Glasgow for cost and availability of the following:-

17 - A012 997 07 45 £0.98
21 - A000 078 01 31 £6.93
22 - A000 997 70 44 £0.83
25 - A000 078 06 80 £31.15
62 - A611 070 03 30 £2.17
116 - A611 070 48 32 £12.01
118 - A601 997 06 45 £0.67
125 - A611 070 73 32 £35.81
137 - A601 997 06 45 £0.67
139 - A006 990 60 40 £1.03
149 - A611 070 49 32 £15.21
161 - A601 997 03 45 £1.45
or A601 997 06 45 £0.67
242 - A6110781241 £1.03

I posted the same over on another forum and someone came back stating that the fuel line clips below the pump should be changed at the same time as they become brittle.

Does anyone know if items 21 & 22 need changed as they are like a compression joint so you would expect the locking nut and "olive" to stay in place.

 

[alexander patie]

21 and 22 do not need changing. the clips under the pump only need changing when they have been broken!!! this is easily done, otherwise they can be used time after time. i would try to pin down EXACTLY where that fuel is coming from as you do not want to try to fit the pump repair kit unless you absolutely have to.

 

[Wully]

i would try to pin down EXACTLY where that fuel is coming from as you do not want to try to fit the pump repair kit unless you absolutely have to.

That statement makes me wonder what is actually in the service kit?

 

[alexander patie]

i have no idea, but if it has seals designed to hold back 7000+ psi then it needs doing properly. it may turn out to just be an oil seal for the drive, and consequenty no use to you, but those low pressure pipe o-rings are favourite i would think? if in doubt steam clean the area thoroughly or blast with brake cleaner untill it is bone dry then get someone to start it while you observe with a torch. if it is leaking profusely and resolutely refusing to start then it could well be the pump itself - they DO leak from those 3x 'caps'.

 

[proser]

You don't the seals for the fule pipes are they come already on new pipes.

 

[Wully]

You don't the seals for the fule pipes are they come already on new pipes.

Is this the o-rings on the pipes are you talking about?

 

[Wully]

This was the temp repair by the AA:-

This is the area where the more serious leak is from, if you look at the bolt its to back of this at the bottom. The seal does look as if its away but it's been like this since i've had the car and thats 3 1/2 years.

This one shows the fuel pipes to the rear covered in diesel:-

 

[Wully]

Just came across this over on the other forum, thanks to T1M4 not sure if he is a member here.

I understand this is a common problem causing either poor starting or the engine to die a second or so after starting then taking lots of cranking over to re start.
It isn’t the pipes themselves rather the seals on the ends that go faulty however, the pipes go brittle and discoloured. As you can see below the four new pipes from the MD dealer. (cost around £40 for the lot)

Firstly you need to remove the engine cover by undoing the six bolts and taking off the oil filler cap (5mm Hex)

This is the first pipe, the smallest which is an easy one to start with
To release the pipes press the white clips inwards and pull the pipes out

The white part of the clip simple pushes forwards.
When you remove the pipe some diesel might leak out so it is a good idea to have a cloth ready to wipe up any spills.

This shows how badly the discolouration is, and the pipes are very brittle.

Push the clip in on the new pipe, clean the mating surface, push the pipe fully home and pull the white clip back out to fix it in.
The next three pipes are a little more difficult because they run around the front of the engine. The next pipe that I did was the long pipe that runs along the top.


Please see part two for the rest instructions many thanks.
Mercedes-Benz Owners' Forums

 

[Wully]

And part 2, thanks again

These two pipes are held in by two clips be careful when removing them that you unclip them from the top because they will break if tried to be unclipped from the bottom.
As you can see from the picture above the clip on the pipe is different to that of the first pipe to get this out, you need an 8mm socket and remove the bolt this then removes the cover and allows the pipe to be removed.

The other end of this pipe is the same as the first pipe. However, I was not able to remove it because I could not push the white clip forward enough, so I cut the pipe this allowed me to turn the clip and remove it.

The next pipe also has a different fitting on one end of it, there is no white part to the clip so this means that at the back of the pipe you need to push the clip so that it releases it and you are able to remove it.

This is the fitting as you can see the fitting gets pushed in at the back and this brings the sides out so that the pipe will come out.
I could not remove the pipe by pushing the clips in so I broke the clips off allowing me to remove the pipe.

At this point both of these pipes need to be changed at the same time because on is behind the other one.

Once all of the pipes are on your engine will have four clean pipes.

May be a good idea to change the fuel filter at this time if it’s anywhere near due. Once your finished all that remains is to crank the engine sufficiently to purge the air. Remember not to crank for too long so as to overheat your starter. Give it a few long cranks then rest for a minute or so. If your battery is not in good order you may find it runs out of charge before the engine fires in which case your going to have to re-charge and try again -- Good Luck !!

 

[Wully]

I'm beginning to think it's the seal on the plastic connector, this photo shows it perfect:-

 

[Dieselman]

I'm beginning to think it's the seal on the plastic connector, this photo shows it perfect:-

It looks like somone has already had a go at yours and added a seal of some sort. Just replace the pipes, yours look old.

 

[Wully]

Update:-

Called the AA back via my Dad who has relay on his membership so we could get the car home.

The guy who turned up was determined to get the car driving again so he set about removing the shut off valve and pipework entering the high pressure pump.

Here is what he found, the one on the left is the supply pipe and the other the return from the rail:-

As a few have mentioned he was sure someone at some stage had been in about this and reused the old seal.

Anyway after making a temp seal the car fired up with no leaks, just need to revise my shopping list now i know what i know! :bannana:

 

[proser]

Is this the o-rings on the pipes are you talking about?

Yes

 

[proser]

From this thread, I have also found that I have a slight leak from the same area on my Merc.

I have ordered the fuel pipe from pump to rail, intermediate pipe and 2x foam washers (even though they didn't show against my vehicle on EPC). Should all be at the dealers for this afternoon.
All other pipes have been replaced due to other issues.

Not sure if this an attributing factor to my RPM limit, but will soon find out

 

[Stratman]

Mods, any chance of adding this to the "How to" section?

 

[Wully]

Well received a call this morning to tell me the parts i had ordered were in and after forking out the grand sum of £77 inc VAT i had them in hand!

Got home from work around half five and went straight to work, two hours later and at the end by torch light the cars back on the road!

The hardest part, the fuel line from the return off the rail back to the high pressure pump. I'm assuming the way the hose if routed that these are installed prior to the installation of the steel pipes leading to the injectors. The hose isn't the problem it's the clips that hold it in thats the problem as there is just no room.

Due to the limited light and clock watching i wasn't able to take photos during the installation but thos previous explain all.

I wonder how much that would have cost in a garage?

 

[alexander patie]

The hardest part, the fuel line from the return off the rail back to the high pressure pump. I'm assuming the way the hose if routed that these are installed prior to the installation of the steel pipes leading to the injectors. The hose isn't the problem it's the clips that hold it in thats the problem as there is just no room.


I wonder how much that would have cost in a garage?

the return pipe IS best fitted with the metal injector pipes removed as you suggest, they are easily removed/refitted and never seem to cause problems. i assume you did this?

expect up to an hour in a workshop.

i am pleased it has cured your leak and starting problem.

 

[simppa80]

From me leaking come under one highpressure pump cap. I got highpressure pump repair kit and change all rings and gasgets so it stopped leaking. Before that I change pipes witch come to highperessure pump. It wont stop leaking.

If we look picture below. Leaking come from under cap witch is under pipes. And diesel leaks just it comes from pipes endings..



These are common faults in MB CDI motor. High pressure pump gasgets and O-rings in diesel line.

AGAIN:
SORRY MY ENGLISH.. HOPE YOU UNDERSTAND WHAT I MEAN..

There is picture of mine: