Unusual automated oil filling

[Old.Tony]

I doubt the DPF has anything to do with it.

The DPF is a soot filter, yes. It has 3 sensors in it: two pressure sensors and a "heated oxygen sensor". The HO2S checks to see how much oxygen is present in the exhaust - if there's not enough for a regen burn, the ECU won't do it.

A regen burn happens (when the conditions are right) by the ECU opening the injectors during an exhaust stroke. For those that don't know, this is when the combustion has just happened, the piston reaches the bottom of its travel and starts coming back up with the exhaust valves open. While these valves are open, the ECU squirts a small amount of fuel into the exhaust stream. This lands on the DPF.

The regen happens under the following conditions:

1) There's a pressure differential between the two pressure sensors
2) The engine RPM are 1600 or more
3) The engine load is below 50%
4) The engine temperature is in "normal" range (coolant between 90 and 105C)

The owners manual says to drive the vehicle at 80km/h - sometimes that's not possible, and in low gear you can maintain 1600rpm and that does the same job (as discovered by Pete).

The DPF light only comes on if the ECU needs to perform a regen and conditions 2, 3 or 4 haven't been met - it's the car saying that it needs to do a regen. Mine's obviously done a LOT of regens in its time and I've only ever seen the light come on during the startup diagnostics.

So, if your injectors are sealing properly, it's not the DPF responsible for this.

Did you test the oil, and is it diesel in there?

I wonder if there could be something wrong with the fuel pump (lower right side of the engine) that could do this? Tweak'e, what do you think, could it be a seal inside the fuel pump?

 

[burgo]

Hi,
Try adding some 2 stroke oil to the fuel and observe results.
If result shows improvement then fuel pump is most likely the problem.
Watch and prey that it takes up???
If you are running a chip that over-rides the C/R fuel pressure then remove it for trial.
Regards
Burgo

 

[daz_rad]

I know there's a load of replies and it seems to be a frustrating issue but I did some research and found out some things that may help.

Has anyone heard of diesel runaway?
Having too high of diesel in your oil mix will cause diesel runaway where the oil is so saturated with diesel that it will become explosive and cause the vehicle to continue running even when turned off.

The particular issue you are getting (increasing oil levels) is the number one symptom for diesel runaway. There are several ways diesel can contaminate your oil but the main reason tends to be worn or damaged pistons.

Wikipedia quote:
"The unwanted oil can also come from failure of the oil seals in a turbocharged diesel engine, from overfilling the crankcase with oil, or certain other mechanical problems such as a broken internal fuel pipe. In vehicles or installations that use both diesel engines and bottled gas, a gas leak into the engine room could also provide fuel for a runaway, via the engine air intake."

I hope that's not your problem but I thought I should mention it as a possibility.

And with regards to the two stroke oil in your engine.... If you decide to do it DO NOT use a high quality synthetic oil because the high ash content will cause you dramas with your DPF. The ratio is 1-200 and a mineral or semi-synthetic oil is recommended.

 

[daz_rad]

Examples of runaway diesel:
http://www.youtube.com/watch?v=3NRaqgab0_w
http://www.youtube.com/watch?v=q4fxjKnuI4Y
http://www.youtube.com/watch?v=5zx3qKX_Pno

Wiki link; runaway diesel:
http://en.m.wikipedia.org/wiki/Diesel_engine_runaway#section_1

Two stroke Oil and diesel engines:
http://www.freel2.com/forum/topic878.html?highlight=oil

Haha found this 15 second YouTube video while researching.
http://www.youtube.com/watch?v=6HuYoFfvl2s

 

[Old.Tony]

Some interesting issues raised there. Most of all the importance of fitting a catch can and caring for your turbocharger!

 

[Damian]

Hi Guys, sorry for the late reply have been really busy.
I have decided to take a bit of a backstep here and get the oil professionally tested. I probably should have done that in the first place but I tend to learn the hard way.

I read online somewhere that a good check for diesel in oil is to put a drop on a paper towel and observe the outer edge of the oil under UV light. Diesel glows in UV light and as diesel is a lighter fluid than oil it should get absorbed faster and further than the heavier oil. So under UV light a halo should appear around the oil drop.
This did not happen.
I am still not convinced that it is not diesel. Simply because it has me stumped as to what else it could be.
So i think it is time to get it professionally tested.

Thanks for the replies, i read everyone with interest.
daz_rad i have heard of diesel runaway, but i have never thought about having too much diesel in the oil could cause it.
Thanks for the youtube links and the tips for the 2 stroke oil. I will remember not to use full synthetic.
Tony i agree, catch cans are a good idea for the turbocharger and the intake system. Or just face the PCV pipe at the ground and hope you don't get caught

I will keep you updated on the results of the testing when they come in.

 

[Old.Tony]

Damian, a new piece of information came to light when I was looking up info for another thread.

One of the problems with biodiesels is that it causes dilution of the sump oil. I don't know how it does it, but you can read about it here.

Are you using biodiesel?

 

[Damian]

Hi Tony,
No i am not using biodiesel. But it makes me wonder after reading your article. It sounds like they mix biodiesel with standard diesel to make it go further.
My question is, do they have to display if the diesel had been mixed with biodiesel?
I'm also unsure how biodiesel itself would cause dilution of the sump oil.
If anyone knows could you please enlighten us.

 

[Jason]

Consumers must be advised if the bio-diesel blend is above 5%.

 

[Damian]

Thanks Jason.
That means i have never used more than a 5% blend of bio-deisel in my navara. So i dont think it could be to blame. Although i am still interested in how bio-diesel would cause dilution of the sump oil?

Update on oil testing:
Dont lose any sleep. I am still waiting for the test kit to reach me in the mail so i can get a sample and post it back for them to test.
So... still awhile!

 

[Damian]

Update:
Test kit arrived. I took a sample of oil and will post tomorrow.

 

[tomo07]

could try contacting the previous owner, if you bought it at a car vard they have to provide contact details of the previous owner by law. I may have a history or they could know. also check the service history stamps in back of owners manual. If the mechanic has been keeping a log, they may be able to shed some light on in.

Also if it is desiel mixing prehaps you could undo the oil sump/box at bottom of engine and look for some build up? just a suggestion. Very unusal thou. Let us know how you get on as you have us all intrigued now, Tomo7

 

[Damian]

Hi Tomo7,
I bought it through a private sale and the owner didn't really know anything about the car because he bought it off a mate. There is no service history, because he didn't have an owners manual. I know it sounds suspect and i was suspicious, but i had a good look through and test drive before i bought it. None of the common problems were evident so i bought it. Price was $16,750 for a 2008 D40 so at that price i didn't mind if i had to fix some things up. Well for that price i knew i would have to fix some things up.
Apart from the problem i am having now, it was mainly blown fuses and relays. So i haven't had to spend much at all.

Update:
No word on oil test yet. I have been pretty busy so i haven't had a chance to call them, but if i haven't got an e-mail tomorrow I'll give them a ring.