W124 E300d Fuel Lines

[SilverSaloon]

Oil will come out, not fuel.
Silversaloon, just take the manifold off, it's going to be sooooo much easier and you can see a lot more.

how much oil? its a fuel leak i have so if there is oil behind am i barking up the wrong tree here?

 

[Dieselman]

Behind there is the rack adjuster mech which is lubed by a bath of oil, so about 1/2 a cupfull.

Just remove the manifold, dry all the leaked oil up and then run the engine and watch for leaks

 

[SilverSaloon]

Behind there is the rack adjuster mech which is lubed by a bath of oil, so about 1/2 a cupfull.

Just remove the manifold, dry all the leaked oil up and then run the engine and watch for leaks

but what i mean is - can this actually leak fuel? if all behind is engine oil?

i have no engine oil leaks - just diesel (veg) leaks

it definatly appears to be leaking from the top of this plate - strangley the bolts (torx 30) didnt seem very tight so i've tightended them up a bit - still leaks though - i guess the gasket may be gone.

cheers

derek

 

[Dieselman]

It shouldn't leak fuel from there as it's part of the lube circuit, unless your pump is different to a normal PE pump.

Have you tried drying and watching closely, I would think it may be leaking from one of the delivery valves and running down or alternatively the fuel inlet.
You won't be able to see properly unless you remove the manifold.

 

[spock500]

Evening all,

Derek, in reply to your message -

The plate gives access to the valve gallery I guess for servicing/ replacement if needed.

Unfortunately tightening the plate bolts will have no effect as the gasket sits in a recess with a metal to metal contact maintained when bolted up.

It took me ages to find the leak as it tracked along the top of the seal before running down the side of the engine, mine had about 100ml of diesel fuel inside but this maybe more if you haven't removed any of the pipes first (see pic) to lessen the pressure.

Dieselman, I think this relates to the earlier pumps as the oil lub doesn't travel this far up into the IP, the fuel circulation is likely to act as a coolant for the pump in this area.

Agree, with Dieselman, the easiest way is to remove the plastic inlet manifold - a set of seals is around £10 for MB dealer and is a good opportunity to remove the EGR build up if you haven't capped it.

There are four nuts (10mm) on two brackets and then 20 odd torx bolts which I loosen with a socket then use a power driver otherwise it takes forever

I can remove mine in less than 15 minutes (did it today to replace all the hydraulic lifters )

Give me a shout if you get stuck -

 

[Number_Cruncher]

>>mine had about 100ml of diesel fuel inside

Generally, as Dieselman has said, there shouldn't be fuel behind that plate.

Also, as Silver Saloon has said the leak is coming from the *top* of the plate, that makes it less likely to be the cause, as there isn't any oil pressure in there as such - it's just oil splash from the IP camshaft.

The leak is, again as per Dieselman's post, more likely to be from the fuel union above the plate, or, if you're unlucky, from the delivery valve seals.

On these engines, there are so many things to inspect, check, and repair which can only really be got at with the manifold off, that it's not worth being shy of the job. Taking the manifold off is really not difficult, and you can even run the engine with the manifold off. Unless you're mechanical skills are worse than Jeremy Clarkson's, you'll be fine.

 

[SilverSaloon]

hmm, thanks all for the advice.

i think i will just bite the bullet and do the delivery valve seals and then start again from there.

 

[Number_Cruncher]

>>do the delivery valve seals

Quite a rollercoaster! From being reluctant about removing the manifold to being bold and brazen about opening up the injector pump in the space of but a few posts!

I'm quite an experienced mechanic, but, you would have to show me incontrovertible evidence that the delivery valve seals needed doing, and twist my arm half way up my back before I would consider touching them! The odds of causing serious damage, and ending up with a badly running engine are just too high - there's a very high failure rate for this job!

Removing the manifold, to inspect, or to ease access for other jobs, on the other hand, is something that I would do without any hesitation - short of dropping serious debris down the inlet ports, there's little chance of doing any damage.

 

[spock500]

NC, I do remember reading a long thread on one of the MB forums related to the different inline pumps -

From memory there was a change over from the type fitted to the W123's
which were oil lubed from the (crank case) to these later units which have very limited oil usage from the engine.

I will have a scan through to see if its still around.

 

[Number_Cruncher]

My understanding is that the earliest, pre W123, pumps were lubricated independantly from the crankcase, and so, checking and changing the IP oil was a service item. From W123 onwards, until the demise of the inline pumps, they were lubricated using crankcase oil, albeit, a restricted supply rather than full flow, full pressure.

However, I'll be the first to admit that there's a good chance I'm completely wrong!

 

[SilverSaloon]

i think i will replace it anyway just incase. This was it will atleast elminate it from my suspicions. The delievery valves dont seem to show any major leaking but lower down it seems pretty bad.

can anyone confirm that part 152 is the gasket required for this face plate?

cheers:

 

[spock500]

Thats the one, have you taken the pump out as I saw another thread?

You will need to reset the IP timing which needs a MB tool, however you can do it with some smoke and mirrors -

If you have the pump off do the bottom seal as well, only £3/4 ea

 

[SilverSaloon]

Thats the one, have you taken the pump out as I saw another thread?

You will need to reset the IP timing which needs a MB tool, however you can do it with some smoke and mirrors -

hi

i've taken off the lift pump and fitted a new gasket and o-ring. seems fine since

if i'm just removing the plate and putting a new gasket on, why do i need to reset the IP timing?

 

[spock500]

'why do i need to reset the IP timing?'

Because you have removed it form the car, the timing is set by loosening the bolts you undid to remove it.

Is the pump still off?

 

[SilverSaloon]

'why do i need to reset the IP timing?'

Because you have removed it form the car, the timing is set by loosening the bolts you undid to remove it.

Is the pump still off?

no its back on the car - i drove it to work today without problems.

i only removed the 2 10mm bolts that just hold the lift pump on.... the pins (that these bolts screw onto #137 in pic above) that screw into the block didnt move. i'm not sure what could have changed. car drives fine.

 

[spock500]

Oh, ok - I thought you had removed the IP as per diagram above instead of just the lift pump - you can do it without the tool using a mirror and torch so not a problem.

Have you had the plate off yet?

How I found mine was leaking was using a a priming bulb I put into the diesel fuel line to prime the system after filter changes ect..

I bypassed the first solenoid which prevent fuel going to the filter with the ignition off, so I can now prime all the way through to IP. However when I did this it was squirting out and hitting various parts around it.

 

[SilverSaloon]

i have not removed the plate yet.

so, just before i do, is it just a case of unscrewing the plate, letting whatever is behind it drain out, fit new gasket and re-screw on....?

nothing else? i plan a big journey in a few weeks time so only really want to perform easy tasks before then. I would really like to cure the leak and i am suspicious of the plate leaking so would be good to do it before i go but if there is a danger of messing about with timing etc i wont....

please let me know

cheers

derek

Oh, ok - I thought you had removed the IP as per diagram above instead of just the lift pump - you can do it without the tool using a mirror and torch so not a problem.

Have you had the plate off yet?

How I found mine was leaking was using a a priming bulb I put into the diesel fuel line to prime the system after filter changes ect..

I bypassed the first solenoid which prevent fuel going to the filter with the ignition off, so I can now prime all the way through to IP. However when I did this it was squirting out and hitting various parts around it.

 

[spock500]

Derek, dont worry about the timing, that was my mistake I assumed you had pulled the whole pump off and not just the lift pump.

Its very easy to change, a 45min job tops if you use the power driver to take out the torx bolts that hold the manifold on. :bannana: there are some pics I posted a while back of the plate and gasket and thats it!

I would torque them up in case the plate gets twisted, do you have the settings? if not I can get them.

You have my number so any probs give me a call,

 

[SilverSaloon]

Derek, dont worry about the timing, that was my mistake I assumed you had pulled the whole pump off and not just the lift pump.

Its very easy to change, a 45min job tops if you use the power driver to take out the torx bolts that hold the manifold on. :bannana: there are some pics I posted a while back of the plate and gasket and thats it!

I would torque them up in case the plate gets twisted, do you have the settings? if not I can get them.

You have my number so any probs give me a call,

i dont have a torque wrench - is this really needed or should i be ok just nipping them tight? i am sure the leak is coming from here, so its worth changing - gasket is just £4 from the dealer.

if you could provide the torque settings it would be good - i can always get cheap wrench.

gasket is ordered from MB so hopefully do it this weekend or sometime in the evening this week.

i appreciate the advice & help

 

[Dieselman]

You won't need to torque them up, just nip them up to a nice hand tightness and you will be fine. Don't overdo it though as they screw into the aluminium head. Get all the bolts back in before tightening up otherwise some holes might not align.

You don't need a new gasket, just rub the rubber coating off the old one if it comes away. There is no pressure or vacuum on yours as it is an atmo diesel, not a turbo.
Even a turbo gasket seals no problem with no problem as it's pressed to form a seal.