Fiat ducato 2.8 oil in diesel fuel tank (1 Viewer)

[candkandb]

How has my engine oil ended up in fuel tank ?

 

[Boringfrog]

I doubt it has, what makes you think it has?

 

[candkandb]

Engine oil nearly empty. Fuel tank full of oil.

 

[Figaro]

Well, never heard that one before ,!
Oil and filter change gone seriously wrong ?
Carried out by Mr Magoo

 

[Boringfrog]

How do you know the fuel tank has all the engine oil in it, which is approximately 6ltrs, and when mixed with the diesel oil I'm not sure you could tell the difference?

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[candkandb]

Engine misfiring badly. Checked fuel filter jet black. Drained fuel tank. Put new diesel in new filter. Started fine. Check today. Put pipe into a bottle more oil than fuel

 

[Figaro]

And before restarting, you topped up the oil where ?
That's really strange. There is no route for engine oil to get back to the fuel tank.
Can you rule out mischief by someone ?

 

[SpeedyDux]

It sounds like a malicious prank. Do you have neighbours who object to your MH?

 

[Steve and Denise]

Do you have a locking cap on the fuel tank?

 

[candkandb]

Never left the van

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[Boringfrog]

Engine misfiring badly. Checked fuel filter jet black. Drained fuel tank. Put new diesel in new filter. Started fine. Check today. Put pipe into a bottle more oil than fuel

Don't know what you mean by "put pipe into a bottle"?
How much diesel did you fill the tank with?

 

[Lofty1]

While I have no experience of this type engine I have had the same thing happen on larger vehicles, the cause was the fuel pump seal between engine and pump letting engine oil into the low pressure side of the fuel pump, cured by fuel pump renewal

 

[Steve and Denise]

While I have no experience of this type engine I have had the same thing happen on larger vehicles, the cause was the fuel pump seal between engine and pump letting engine oil into the low pressure side of the fuel pump, cured by fuel pump renewal

The pump on this van will be belt drive so no connection to crankcase.

 

[Lofty1]

The pump on this van will be belt drive so no connection to crankcase.

Next question is has it a fuel warmer or oil cooler?

 

[Misterg]

fuel filter jet black

That sounds like 'diesel bug' due to water in fuel (yes, it will stop an engine)

(That's a diesel filter, btw, not an oil filter.)

Put pipe into a bottle more oil than fuel

Oil and diesel would mix. Are you seeing an oily looking fluid that the diesel floats on top of? If so, it's bacteria infested water and consistent with the clogged fuel filter.

There are chemical treatments that will kill the bug and remove the last traces of water (but it would be wise to remove as much water as possible first). Used to use something called Grotmar 71 on the boat seemed to work well.

Don't know where your oil went, sorry.

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[mfw]

If you had a problem with a worn engine could oil blow back past injectors into fuel tank taking account of ignition pressure within combustion chamber - diesel engines are compression ignition so some serious pressure within combustion chamber

 

[Lofty1]

That sounds like 'diesel bug' due to water in fuel (yes, it will stop an engine)

View attachment 277742

(That's a diesel filter, btw, not an oil filter.)



Oil and diesel would mix. Are you seeing an oily looking fluid that the diesel floats on top of? If so, it's bacteria infested water and consistent with the clogged fuel filter.

There are chemical treatments that will kill the bug and remove the last traces of water (but it would be wise to remove as much water as possible first). Used to use something called Grotmar 71 on the boat seemed to work well.

Don't know where your oil went, sorry.

This was a major problem caused by bio fuel on engines that had fuel heaters or the tanks that it was stored in got warm it cost the company I worked for many hundreds of pounds for each vehicle to clean the systems and change filters and m-prop valves. bio fuel is not the best idea.

 

[Lenny HB]

While I have no experience of this type engine I have had the same thing happen on larger vehicles, the cause was the fuel pump seal between engine and pump letting engine oil into the low pressure side of the fuel pump, cured by fuel pump renewal

Aren't Ducato fuel pumps electric?

 

[Pausim]

That filter looks very much like the dreaded diesel bug and when I got it in one of my boats it looked like a black oily sludge in both tanks. If it really is oil in the fuel tank the only source I can think of is engine oil being drawn into the diesel return system but I am no expert and I would be heading for a workshop.

 

[Snowbird]

Am with the diesel bug on this one. If your van has been parked up for any length of time with little fuel in it there is a strong chance of diesel bug. When parking the van up over winter or for any length of time it is always advisable to fill the fuel tank. This decreases the chance of condensation in the tank, which is the main cause of diesel bug.

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[Just smiffy]

Ask short questions, get short answers....

 

[Lofty1]

Aren't Ducato fuel pumps electric?

Not the fuel lift pump but the high pressure injection pump on some vehicles this is a combined unit

 

[jezport]

My Money is on diesel bug.

 

[mfw]

If the OP is losing engine oil and not burning or leaking oil the only way to get in tank is via fuel line it is only bit they share via the injectors

 

[Figaro]

My Money is on diesel bug

Never heard of it before, is it something else to worry about ? I'll add it to my worry list.
Luckily I always keep the tank full over winter anyway.

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[mfw]

Try getting a cylinder compression test on engine that should help and see if the pressure drops on 1 cylinder

 

[ambulancekidd]

 

[tonyidle]

If you had a problem with a worn engine could oil blow back past injectors into fuel tank taking account of ignition pressure within combustion chamber - diesel engines are compression ignition so some serious pressure within combustion chamber

No that could never happen - the pressure needed to open the injectors is well in excess of the combustion pressure. If it wasn't the engine wouldn't ever work. There is no way on earth that engine oil can end up in the fuel tank because of any engine fault. Even if it had been poured into the fuel tank it would mix with the Diesel, the engine would continue to run, and the fuel filter would not clog. The only symptom would be a very smoky exhaust and even for that to happen there'd need to be a very large amount of oil mixed with the Diesel.

 

[pappajohn]

No that could never happen - the pressure needed to open the injectors is well in excess of the combustion pressure

Precisely.....
Cylinder pressure on compression stroke approx 300psi to 330psi
Injector pressure at injection 36000psi

And if it could happen it would only force the tiniest amount of diesel back through the injector, there is no oil in the combustion chamber to speak of to be forced back.

 

[Two on Tour]

So where you though you only had one problem now you have 2 for the price of one, where's me engine oil going and what's the crap in me fuel tank.

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