Oil level rising

[Jonatanso]

Hey guys, i am new to the forum and i signed up as i need some help with my polo.

The vehicle is a vw polo 1998 1.7 SDI. I have converted it to run on waste vegetable oil and waste motor oil. I have made a heating system for it and it is a one tank system.

The problem that i have encountered now is that the oil level in the sump is rising, there is no signs of water contamination.
When i say the level is rising, i mean that the oil level goes from min up to max in around two weeks or around 400-500 km. I check the oil under the same terms everytime, same level ground, 10-15 mins after driving and through the two week span i can see that it is rising consistently.

I am currently running on waste motor oil so i am not worried about the oil being contaminated with diesel or vegetable oil, i usually drain off the oil from max to min when it gets to that level.

I have read that on TDI engines it can be caused by the tandem pump, however this is a SDI and i dont think it has a tandem pump(correct me if i am mistaken)
The fuel pump looks to be separated from the engine block, as in a mounted part onto it, so i ser no way for fuel to be leaking from the pump to the engine oil.
I have been onto the thought of it maybe being from the injector, however i cannot figure out how it is even possible.

Help and suggestions would be very much appreciated!

In advance, thank you!

[Jonatanso]

vag-com.jpg

I was able to connect vag-com to my little polo this morning, one thing i noticed is that group 013 was not updating while i was driving. it only updated when i pushed the clutch in and load went down to 0%
vag-com2.jpg

I do not know how accurate these readings are, is it possible for the fuel to be coming from the injectors without me being able to see excessive amounts coming in the injection quantity(in the readings from veg-com)?

I would appreciate any help with this as i am out of ideas!

Thank you!

[Jonatanso]

I was able to solve my problem, without much help from here, although it is understandable as it is not a common problem. anyway, instead of letting this thread die without being resolved i thought i'd post what i did to fix this.

Before i say what i did, i would just like to inform that this is not the "right" way to solve this, but it is how i did it.

I took out the injectors on saturday, and found that there was a thick, hard layer of soot on the nozzle tip covering the holes, thickness around 3-4 mm. I think around 70% of the nozzle holes were covered with the carbon/soot so drastically decreasing the spray pattern and hindering clean combustions. i believe this was also the cause for my oil level to increase. I cleaned the outside of the nozzle first with a brass wirebrush but without any good result, the carbon was really stuck. i found some 1200 grid paper and polished it down so all the holes in the nozzles were visable.
After polishing i soaked the nozzle tips in injector cleaning chemical for an hour, then wiped down the injector.(i dont think the injector chemical did anything helpful, but i found it lying around so i just tried it)
I reused the old copper washer but i heated and shock cooled it first to soften it before mounting the injectors back into the engine.
I did not open the nozzles, only cleaned the outside.

now, i know i probably should get new nozzles, but its and old car and as long as it works without problems, my conscious is clear.

another symptom my car had that i forgot to mention is that after idling it for 10-15 mins i would get a huge white cloud from the exhaust if i floor the throttle, now after cleaning the outside of the nozzles, when i idle 10-15 mins and floor the throttle, all i get is a small "poof" black cloud that quickly diapers, like a normal car would give off

I hope this post may be of any use to anyone facing the problems as me.

Good luck with your car!

[FrenchAudi]

I'm not surprised at your engine running on waste and chip oil has large carbon deposits, and you've only seen what was on the injectors.

The last time I met someone running a diesel on chip oil, the engine was wrecked, and he was stranded in Spain, because the injection pump siezed up with carp and stripped the drive gears.

It was an old Perkins engine with gear driven accessories, so no chain nor belt, but I imagine the result of a siezed injection pump with a belt drive would be equally drastic.

[Jonatanso]

I'm not surprised either about the carbon buildup, although with the age of the car it is normal for things to break and build up so i don't think blaming it solely on the wvo is right, the car was really slow and dead when i first bought it as well. Now i am also not saying wvo is "good" for the car, but it will run on it.

I fail to see how this could seize up the injector pump, i understand carbon in the combustion chamber but that would fail to make a way to the pump, premature wear of the pump is in my opinion more likely to happen, i filter my oil and make sure it is clean, it's not like i pour french friends into my tank.

Since i bought the car, i have driven 12000 km, after first 4000km i saved up for the worth of the car, by not pumping diesel. At 7000 km i saved up for everything is spent on repairs, so after 7k the car basically runs for free and has is saving me money.
So even if i need to pull off the head when i reach 20000 km to clean everything and resurface it, i would still be saving money from running on vegetable oil

However, this being said, i would not recommend running on wvo to anyone who is not able to fix their own car. This is something i enjoy and i have have an understanding about, i am also not afraid to take thing apart just to look at them, like i did with the injectors.

All the best!

[FrenchAudi]

Vegetable oil tends to form gum or varnish after heating and re-cooling. This was the problem found when castor oil was used to lubricate racing engines many years ago, and the oil had to be drained from the engines while still hot to avoid it.

The consensus was that the injection pump siezed due to the build up of gum in the small clearances inside.

Believe me, it was well siezed to strip the teeth on the timing gears, they look like this Perkins 6-354 timing.jpg

[FrenchAudi]

Vegetable oil tends to form gum or varnish after heating and re-cooling. This was the problem found when castor oil was used to lubricate racing engines many years ago, and the oil had to be drained from the engines while still hot to avoid it.

The consensus was that the injection pump siezed due to the build up of gum in the small clearances inside.

Believe me, it was well siezed to strip the teeth on the timing gears, they look like this, the injection pump gear is at the top right.


Perkins 6-354 timing.jpg

[Jonatanso]

Hmmmm, i see your point now. Maybe i should take apart the fuel pump when i reach 20000km with wvo, to inspect, clean and put on new seals just to be safe. If the timing belt snaps, my engine would RIP.

Thank you for your input.

[FrenchAudi]

My pleasure.

Better safe than sorry. I met the guy in Spain, at the Perkins agent. He had been waiting several days while they sourced a new idler gear for him, and it was not cheap.

He said the crankshaft gear was still OK, but seemed to be unaware that there might be other damage to the engine, such as bent valves or broken pistons. He said he would see what happened when he got it running

[Jonatanso]

Just a little update,
I am STUPID!!

I took the injectors out again, and put them in a testing bench. I testes all the injectors and the result was as following
1- opens at 175 bar, good spread. "cuts" the flow nicely and makes the right sound
2- opens at 180 bar, good spread. "cuts" the flow nicely and makes the right sound
3- opens at 185 bar, good spread. "cuts" the flow nicely and makes the right sound
4- opens at 180 bar, good spread. "cuts" the flow nicely and makes the right sound
The injector is supposed to open at 190, so with the lowest being 175 i would say this is acceptable for my beater car.
Now, to the fun part....
an old retired engineer came to me and told me i should clean the tips with sandpaper and found some 180 grit for me, i was really skeptical and he noticed that. i did not use the sandpaper but he came to me a little later with a file cleaner that looks like a regular wirebrush and told me to use this, i tried carefully and it did not make any scratches or marks and was really good at removing the dirt and carbon, i cleaned all the injectors with this and tested them before putting back in the car, testing result was same as above.

The car started right away and ran perfect, almost too good to be true.... and one thing i realized while driving is that it was a little slow and weak. The worst was driving up the underwater tunnel with a steep climb, i usually driver at 80 km/h in 4th gear no problem, now the car had no power at all, speed kept reducing untill i was forced down to 2nd gear going at 40.....

most likely what has happened is that i deformed the holes on the nozzle with the file cleaner, so what i did to "fix" this was to polish the nozzles with 1200 grid sandaper, i took my time and ensured that i was doing it at the correct angle etc.... and put the injectors back in. now the engine is running like before, oil level is also stable.

I really want to buy new nozzles, but i cannot find any nozzles for my 1.7 SDI with a reasonable price, would anyone be able to help me here? anything over 50£ per nozzle i consider as too expensive and would rather just drive the car untill its scrap.