Engine Oil In The Diesel Fuel Mondeo MK3

[SimonTheSailor]

Put this in the Ford section but no luck there so thought I'd give a go here !! -

After just having the aux belt and stuff and crankshaft pulley done I've now found the following -

After performing a leak down test and finding that I have two injectors leaking quite badly, I also have engine oil in the fuel.

Somebody has already suggested that it could be an oil seal that is between the fuel pump, when this leaks engine oil can get into the fuel.

Bearing in mind the value of the car I have to try and work out if this is worth continuing with.

Let's say it is this oil seal, do they normally just go by themselves or is it a symptom of something more serious happening ?

I've heard of the horror stories about the pumps breaking up and swarf getting around every part of the engine - game over on a 15 year old Ford.

I have taken the fuel filter off and drained the fuel - examined it for any metal particles - if there was anything there may have been one tiny particle but that was it. It did have what appeared to be some engine oil.

[E-bmw]

Let me get this right, you think you have engine oil in your fuel tank?

And you think a fuel pump o-ring can cause this?

Your fuel pump is electrical with no route to the engine oil.

[tight fart]

How do you know it’s engine oil in the fuel and not a tank of dodgy fuel?
Has the engine oil level dropped?
Old deisels will run on engine oil.

[SimonTheSailor]

Somebody did suggest yesterday about a dodgy tank of fuel especially with the fuel 'crisis' and forecourts getting low/empty.

Can they really deliver something like that ? Surely it must be highly filtered on the out as well as the way in ? Otherwise people would be suing the arse off them if problems occured ?

Edited by SimonTheSailor on Wednesday 27th October 09:48

[SimonTheSailor]

E-bmw said:

Let me get this right, you think you have engine oil in your fuel tank?

Well, in the fuel somewhere.

E-bmw said:

And you think a fuel pump o-ring can cause this?

No idea if it's an o-ring.

E-bmw said:

Your fuel pump is electrical with no route to the engine oil.

I thought it is driven by the timing chain ?

[oakdale]

SimonTheSailor said:

I thought it is driven by the timing chain ?

Correct, injection pump is driven by the chain.

[oakdale]

How dirty/black is the fuel? Try leaving some of it in a container to see if any of the black settles out of the diesel, a faulty injector can sometimes generate dirty leakback due to contamination from combustion.

Edited by oakdale on Wednesday 27th October 10:52

[SimonTheSailor]

This is what happened at the beginning, forgot to take a later photo as tubes 3 and 4 filled up quite quickly.

You see the tube going into number 2 is very black, it soon got more diluted and just looked like discoloured fuel rather than black. Injectors 3 and 4 are leaking badly.

You'll see the fuel going through tubes 3 and 4 looks clean so maybe some oil gets backed up in the injector until it's released this way ?



Found this thread which states about an oil seal breaking down on the fuel pump which then sucks oil through -

Interesting thread I just found -

http://www.talkford.com/community/topic/222667-bla...

Of course they didn't update the thread at the end

[oakdale]

SimonTheSailor said:

This is what happened at the beginning, forgot to take a later photo as tubes 3 and 4 filled up quite quickly.

You see the tube going into number 2 is very black, it soon got more diluted and just looked like discoloured fuel rather than black. Injectors 3 and 4 are leaking badly.



Found this thread which states about an oil seal breaking down on the fuel pump which then sucks oil through -

Interesting thread I just found -

http://www.talkford.com/community/topic/222667-bla...

Of course they didn't update the thread at the end

Looks like number two injector is the culprit to me, the fuel in the pipes looks quite clear on the others and bearing in mind that it's common rail, if it was the pump seal all the fuel would be contaminated.

[SimonTheSailor]

But the stuff in tubes 3 and 4 is contaminated, it's dark in the bottles, the fuel just seem to clear a bit after running for a short while.

Oddly enough injector number 2 is the newest of the injectors and therefore leaks back the least ?

[E-bmw]

oakdale said:

SimonTheSailor said:

I thought it is driven by the timing chain ?

Correct, injection pump is driven by the chain.

I stand corrected.

[Maxdecel]

oakdale said:

Looks like number two injector is the culprit to me, the fuel in the pipes looks quite clear on the others and bearing in mind that it's common rail, if it was the pump seal all the fuel would be contaminated.

SimonTheSailor said:

But the stuff in tubes 3 and 4 is contaminated, it's dark in the bottles, the fuel just seem to clear a bit after running for a short while. Oddly enough injector number 2 is the newest of the injectors and therefore leaks back the least ?

What about #1 ? Bearing in mind Oakdale's txt in bold. New(est) doesn't guarantee functionality !
If #1 is clear is it possible to change with #2 ? (Worst ?) Then test, if the problem shifts voilà. Surely if it's an internal leak the pipes wouldn't clear ?

[SimonTheSailor]

Yes, they were all contaminated. None of them had golden diesel fuel. All were darkened to a fair degree.

[oakdale]

Don't forget the leak back pipes are all interconnected, if the fuel runs clear after the initial black bit, I doubt the pump is at fault.
When these engines were designed, common rail technology was in its infancy and the injectors never were the best.

[oakdale]

Thinking further about this, it's a job to know which injector (if any) the contamination is coming from due to 1 and 2 not leaking back much, I'd run it for a quite a while at different rev ranges with the pipes going to a large container to see what's going on.

What mileage has it done and is it running ok?

[SimonTheSailor]

Yes bit of an odd one isn't it ?!

Mileage is 130K and is running pretty good, no excessive smoke, great fuel economy, very low oil consumption, starts immediately hot or cold.

The only thing it is doing, which is why I did the leak down test, is if you are trying to keep a steady speed you feel it 'pulsating' a bit, like dropping power marginally and coming back but it's very minor.

I'm putting that down to injectors 3 and 4 being bad at the minute as these are the symptoms it displayed when injectors 1 and 2 were found to be leaking badly a couple of years back. In fact it was worse then as it gave me starting problems as well and threw up low fuel pressure codes which the current situation is not doing

[Chris32345]

E-bmw said:

Let me get this right, you think you have engine oil in your fuel tank?

And you think a fuel pump o-ring can cause this?

Your fuel pump is electrical with no route to the engine oil.

Modern high pressure fuel pump are usually cam shaft or chain driven
He dosnt mean the electric low pressure pump if it has one

[SimonTheSailor]

Found this thread where the guy was having a similar problem.
I've assumed all along it was oil but maybe it isn't ? Maybe it's burnt/contaminated diesel ?

https://www.talkford.com/threads/dirty-leak-off-fu...

Why he had two dirty and two clean doesn't make sense because it should get recirculated and just dirty the colour of fuel I would of thought.

But he's changed his offending injectors and the car is running well with clean fuel

So I'm keeping my fingers crossed and changing my two dodgy injectors.

[stevieturbo]

If there is dirty fuel leaking back from only one injector....seems most probable there is an issue with that injector.