Fuel Leak: Causes & Solutions

Okay, since Lukas isn't responding, I'll try it here:
Ich habe ein Problem mit meinem 88er Ford Orion 1.6d, gekauft für 300 Euro im November 2002. Beim Kauf sprang er schlecht an und nahm schlecht Gas an. Ich habe Dieselfilter, Glühkerzen und Einspritzpumpe (EP für 160 Euro, Schrottplatz) getauscht, der Wagen lief einwandfrei – für ein paar hundert Kilometer, dann sprang der Wagen wieder schlecht an und nahm schlecht Gas an. Schliesslich blieb er auf der Autobahn stehen und genervt habe ich den ADAC gerufen. Der hat den kleinen Zusatzfilter (verd..., wie konnte ich den nur vergessen?) vor dem eigentlichen Dieselfilter getauscht und der Wagen lief einwandfrei – für ein paar hundert Kilometer, dann sprang der Wagen wieder schlecht an und nahm schlecht Gas an. Ich habe erneut den kleinen Zusatzfilter getauscht und nun sprang der Wagen noch schlechter an und ich konnte gar nicht mehr fahren: Der Wagen zog Falschluft an der Verbindung Kraftstoffleitung und Zusatzfilter an. Was würdet ihr tun? Den kleinen Filter komplett weglassen und eine neue Kraftstoffleitung verlegen? Da ich aber vorhabe, nach Albanien und Makedonien zu fahren und der Kraftstoff dort alles andere als sauber ist, würde ich nur ungern den grossen und teuren Filter riskieren. There must be a way to seal the connection with the additional filter!
Regards,
A.

Rubber hoses degrade over time and lose their elasticity.
I would therefore start by trying new hoses. Of course, the hoses, or the old ones, must be the correct diameter to fit the filter, meaning they should fit quite snugly even without clamps.
Christian.

Hello,

What is the "supplementary filter" clogged with? Rust or sediment from the tank?
Then you can either change the filter 100 times or verschandeln everything 1 time properly.

Best regards, Rainer.

Thank you for your response. I suspect the additional filter is clogged due to sediment buildup from the old diesel fuel, as the car has been sitting unused for a long time, about a year. That's also why it's drawing in air, because the vacuum pressure is too high due to the clogged filter and the dirty strainer in the fuel tank line. I would also like to verschandeln the fuel tank strainer. Has anyone here had experience with that on a Ford Escort/Orion? Or do additives that dissolve deposits help? I will also replace the old, porous hose at some point; fortunately, there are junkyards around...
The new filter, which I installed myself, might have been undersized, which is probably why it didn't work.
Regards,
A.

The new filter, which I installed myself, might have been undersized, which is probably why it didn't work.
Regards,
A.

Hello Anton,
Was that a small part, like the ones used in motorcycles?
They probably only work with gasoline.

Regards,
Eike.

Yes, I also think it was the wrong filter. To rule out another potential cause of error, I also replaced the gas cap. I thought maybe the old one wasn't sealing properly, which could have created a vacuum in the tank.
Unfortunately, that didn't help either. I really hope it's just the fuel filter and not something like the previous owner using biodiesel, which could have swollen the lines and is now affecting the diesel flow. I'm starting to lose patience with this diesel engine. It's my first diesel car, and it's quite economical – if only there weren't this problem with the diesel line. The filter is full of air; it's definitely not getting enough diesel. I'm afraid that eventually, all that cranking during startup will drain the battery if I don't solve this problem soon.
Regards,
Anton.

Hi Anton,

Unfortunately, my previous car had a rusty container with a diesel-like substance poured into the fuel tank. This resulted in very fine rust particles contaminating the fuel, which cost me two diesel filters and a large number of pre-filters (the ones that attach to the hose).
Additives cannot solve the problem because they only create more loose debris that circulates within the fuel system.
It's better to thoroughly verschandeln the entire system; I actually removed the fuel tank sender back then in order to be able to verschandeln and flush the tank.

Best regards, Rainer.

Hi Anton,

Unfortunately, I poured a rusty container with a diesel-like substance into the fuel tank of my previous car.

Hello Rainer,

was meinst Du mit 'dieselähnlichen Inhalt' ? Kerosin, WD40,...? Heating oil?!?

@ Anton: Does your car have a diesel filter with 4 connections (for the filter itself and fuel preheating), or does it only have one inlet and one outlet?

'Rainer, is there overpressure or possibly even underpressure in the return line from the engine to the filter when the engine is running? Could air be drawn into the system through a leak somewhere between the injectors and the filter?'

'Hey Anton, how are the outside temperatures where you are? We're currently experiencing nighttime lows of down to -15 degrees Celsius here. Could there be condensation freezing in your tank, or is the fuel line possibly blocked by tiny ice crystals in the diesel?'

Regards,

Eike.

Okay, today it was finally determined what the problem is: The workshop, a VW service center and the only one in Gundelsheim, discovered a leak at the transition point between the injector nozzle and the cylinder head. The mechanic sprayed some liquid on it to diagnose the issue. He will start working on the repair tomorrow. I hope the leak is caused by a missing sealing ring and not by a crack in the cylinder head. Man, I'm just unlucky with this car. And of all times, now that I'm already short on money because I lost my job. As they say: Misfortune never comes singly. And I was trying to save money with this diesel engine...
Hopefully, you'll have better luck with your cars!
Best regards and thank you again for your help.
Anton.

Hi,

eike wrote:

was meinst Du mit "dieselähnlichen Inhalt" ? Kerosin, WD40,...? Heating oil?!?

It was oil-like and smelled like diesel, so I poured it into the tank without thinking, because the car was anyway ready for the junkyard .

Quote:

@ Rainer: Is there excessive pressure, or possibly even a vacuum, in the return line from the engine to the filter when the engine is running?

I can only speak from my experience with my car, but there's a T-valve in the diesel filter that, when the fuel is very cold, allows it to recirculate back through the filter instead of going directly to the ESP (Exhaust Gas Recirculation) system.
Therefore, with cold fuel, a vacuum should exist in the return lines from the electronic fuel pump (ESP) to the diesel filter.
If the T-valve allows the return flow back to the tank, there should be no significant pressure or vacuum in that line.

Quote:

Could it be possible that air is being sucked into the system through a leak between the nozzles and the filter?

In my car, this only happens when the T-valve directs fuel back into the diesel filter.
However, this doesn't really help Anton much.

@Anton: What have you done now?
- Are the hoses to the pre-filter sealed tightly?
- Is there still air in the (transparent?) hose between the diesel filter and the fuel injection pump?

Best regards, Rainer.

Hello Eike and Rainer,
'No, my car is a very basic model; it doesn't have fuel preheating or filter preheating, just an inlet and outlet. But isn't winter diesel supposed to be safe down to -22 degrees Celsius? Oh yes, the condensation! Sorry, I don't have any experience with diesels, but wouldn't condensation also freeze in a gasoline tank? If that's a characteristic specific to diesels, then maybe I should only drive my 1988 Orion in the summer or eventually buy a diesel with fuel preheating, as you described. The temperature here in Baden-Württemberg, especially in this part of the Neckar valley, rarely drops below -10 degrees Celsius.'

'In the transparent pre-filter, the diesel fuel immediately flows back as soon as I turn off the engine, leaving only air in the filter, which then requires several minutes of cranking to start. This has been happening so far. However, now the filter also empties when I give it too much gas, causing the engine to stall: again, requiring minutes of cranking!'

I hadn't even thought of the idea of using a transparent fuel line between the EP (electronic power control) and the E-nozzles yet!

'No, I haven't replaced the fuel lines. In fact, just as I was on my way to the scrap yard to verschandeln the fuel filter screen, the car stopped right near the workshop. So, I went there instead. The mechanic diagnosed a leak between the injector and the cylinder head and wants to disassemble it tomorrow to take a closer look. The car is drawing in false air, which means there's no longer enough vacuum in the system, hence the problems with the diesel supply.'
Oh God, I hope this isn't a scammer! I've had really bad experiences with workshops before. Nowadays, scrap metal dealers actually seem to be the most honest ones.
'Happy are those who don't have to rely on a repair shop.'
Goodbye.
Anton.

'Sorry if I don't reply immediately; unfortunately, I don't have an unlimited data plan and am only online occasionally. @Eike: What exactly is WD40? And does kerosene work too? I knew about the wood, but that's prohibited. How about the other two things? Are they winter-resistant? Where can I get them? How much do they cost? Thanks in advance for your tips/explanations.'
Regards,
Anton.

Nonsense, what was that mechanic talking about? There's supposed to be pressure between the fuel injector and the cylinder head, because it's located after the electronic stability program (ESP), not in front of it. I knew it; either this guy has no clue or he's trying to pull a fast one on me.
I'm curious to see what he will tell me tomorrow.
Regards,
Anton.

Hi Anton,

It can't be that bad, right? How many kilometers are on your engine, and especially the ESP (Electronic Stability Program)?
I'm almost certain you have leaky hoses around the ESP supply system, or a defective shaft seal on the injection pump (which is bad).
If the crankshaft seal on the ESP is defective, I would carefully consider whether it's worth repairing a car that costs only €300.

There will never be a transparent hose between the fuel injection pump and the injectors; the pressure there is simply too high for that.

Water dissolves in gasoline to a certain extent, but hardly at all in diesel fuel.
That's why it accumulates at the bottom of the diesel filter.
Unless your fuel filler neck is rusted through or someone has urinated in your gas tank, water shouldn't be a major problem. So far, I haven't encountered any diesel that failed to work with winter-grade diesel even at temperatures of -25°C and below. For example, Austria has a very high percentage of diesel vehicles... just for context.

So, please check the hoses leading to the ESP meticulously, centimeter by centimeter!
If your new "pre-filter" is full of air, it's unlikely to be clogged.

Best regards, Rainer.

Hi Rainer,

The mechanic was a young guy, and I'll give him the benefit of the doubt that he didn't want to rip me off, but he probably just lacked experience. The master technician presented me with an invoice for just over €28 – they replaced the supply line to the pre-filter. I felt relieved. You and Christians were right; the rubber had become hard due to aging and, acutely, because of the cold, and even the hose clamps couldn't fix it anymore.
Now I'm curious to see if this is the final solution to the problems. At least today, the car drove perfectly well.
Thanks again to Rainer, Eicke, and Christians – I will definitely recommend this page to everyone.

Regards,
Anton.

PS: The exact mileage of the Ford will probably remain a mystery forever, as Ford didn't consider it necessary to include a hundred-thousand-kilometer marker on the speedometer for this model. Currently, the display shows 40,000 km, but it could be 140,000 or even 240,000. The ESP (Electronic Stability Program) is used and came from a scrapyard because the Ford workshop (Kohlhoff, Ludwigshafen, Master Lenz) said it was defective, and a new one would cost 1,000 euros (excluding installation), so they suggested I scrap the car... Since then, I've avoided large authorized workshops.

Hi Rainer, one more thing about the transparent hose: Sure, the pressure is too high between the ESP and the injector (okay, next time I'll read the correction ), of course I meant the hose between the ESP and the diesel filter – that would have the advantage of being able to tell whether the problem lies at the diesel filter or at the pre-filter. It's actually incomprehensible that transparent hoses aren't used everywhere to make troubleshooting easier...
Regards,
Anton.