Is increased engine oil consumption due to biodiesel normal, or is the ESD (Engine Safety Device) failing?

Hello!
I'm just going to post my question in the new forum again, otherwise nobody will find it .

What concerns me slightly is that my engine (A4 AFN, year 1996, 262,000 km) doesn't seem to be consuming any oil (using 5W40). I do a lot of short trips, about 15 km each way to work, and I use biodiesel, which doesn't evaporate once it gets into the engine oil. The oil dipstick also smells a bit like a fast-food restaurant (well, at least it smells different from 'normal').

With a 30% content of pure vegetable oil in the biodiesel, this effect was even more pronounced, as the oil level would automatically exceed the maximum level. So, I quickly stopped using that vegetable oil. (It's been much longer than just an oil change, so the smell of fries must be coming from the biodiesel.)

How do worn fuel injectors manifest themselves? Could one be spraying fuel at an angle against the cylinder wall, or would that have already caused a major engine failure? Interestingly, it doesn't produce noticeable black smoke, except for a puff of blue smoke when starting.

Regards,
Udo.

...because if the seals are no longer functioning properly, it can lead to increased fuel entering the engine oil through the cylinder walls.
"With a distance of 15km each way, I'm ruling out condensation in the engine oil. 15km should be enough to properly warm up the engine (what's the purpose of the temperature gauge then?)." (Keyword: Thermostat).
Given your mileage, I would definitely recommend having the spray pattern of the injectors checked or even replaced. According to the experiences of other forum members, fuel injectors are likely to fail after around 200,000 km.

Best regards, Rainer.

Hello Rainer, hello everyone!

With the current outdoor temperatures, the coolant temperature gauge is just barely reaching 90° when I arrive! Should the increased fuel consumption be an indication of excessive wear on the electronic stability control (ESC) system? I'm not able to achieve fuel consumption below 5.4 liters per 100 kilometers, especially with short trips and lower outside temperatures, where it's closer to 5.8 liters.

How concerning is biodiesel in engine oil? Will my auxiliary fine filter help? It might be able to filter out polymerized, resinous biodiesel (polymerization byproducts). It was at least a theory that was discussed in the Fatty-Fuels forum.
Biodiesel also provides a bit of lubrication...

I'll find out how much it costs to have nozzles tested.

Regards,
Udo.

Hi,

I went to ATU yesterday. They can test your injectors (but they can't adjust them). For my TDI, it takes about half an hour just for the testing, and about an hour for the installation and removal. So, they would be charging around 75 euros just for the review.

It probably wouldn't be too different with the TDI.

They didn't have those ESD (electrostatic discharge) devices in stock, so you would have to pay for installation and removal twice, or you could order the ESD devices as a trial run in case one turns out to be defective.

The suggestion was then: 'It's better to have it done at VW.'

I would say that disassembling the injectors is actually easier (and faster) on a TDI engine; they are simply plugged in and held in place with a bracket.

To have the ESD checked, I would go to a Bosch service center (one with a good diesel department).

Once the nozzles are installed, you should have the compression checked.

Blue smoke during startup can be normal to a certain extent, but if you see a cloud of smoke that is opaque, then there is likely a defect or significant wear.

Best regards,
Bertil

Thank you + Hello!

Due to jet testing:
It seems like it's largely a matter of trust, as someone with experience needs to assess the spray pattern. Unfortunately, my trust in the workshop I usually go to has been somewhat shaken recently...

Blue smoke:
I wouldn't call that a thick cloud that appears during startup, more like a small puff of smoke. But what I've also noticed is the smell of the exhaust. Immediately after starting the engine when it's cold, the smell of biodiesel is very strong, but even when the engine is warm, you can easily tell from the smell of the exhaust that I'm using biodiesel. Unfortunately, I don't know anyone to compare the exhaust smell with directly.

Exhaust test:
Today, I repeated the blow-by test at the engine oil filler neck (as discussed in the old forum) with a warm engine, and I noticed that it's blowing out much less air now?! The first test was done with a cold engine right after starting, and it blew out more air then. I would have actually expected the opposite, as colder, more viscous oil should, in theory, have a greater sealing effect on the cylinder bore surfaces.

A sheet of paper won't simply blow away; it's more likely to oscillate (and get soaked).
Test it again tomorrow morning with the paper, using a cold engine.

I won't be ordering any new ESDs based on suspicion; they're simply too expensive. What I'm still interested in is how dangerous the biodiesel content is in engine oil.

Bye.
Udo.

Thank you + Hello!

Due to jet testing:
It seems like it's largely a matter of trust, as someone with experience needs to assess the spray pattern. Unfortunately, my trust in the workshop I usually go to has been somewhat shaken recently...

Blue smoke:
I wouldn't call that a thick cloud that appears during startup, more like a small puff of smoke. But what I've also noticed is the smell of the exhaust. Immediately after starting the engine when it's cold, the smell of biodiesel is very strong, but even when the engine is warm, you can easily tell from the smell of the exhaust that I'm using biodiesel. Unfortunately, I don't know anyone to compare the exhaust smell with directly.

Exhaust test:
Today, I repeated the blow-by test at the engine oil filler neck (as discussed in the old forum) with a warm engine, and I noticed that it's blowing out much less air now?! The first test was done with a cold engine right after starting, and it blew out more air then. I would have actually expected the opposite, as colder, more viscous oil should, in theory, have a greater sealing effect on the cylinder bore surfaces.

A sheet of paper won't simply blow away; it's more likely to oscillate (and get soaked).
Test it again tomorrow morning with the paper, using a cold engine.

I won't be ordering any new ESDs based on suspicion; they're simply too expensive. What I'm still interested in is how dangerous the biodiesel content is in engine oil.

Bye.
Udo

Hello Udo,
I drove my TDI (Golf III, 90 hp) almost exclusively (about 97%) on biodiesel from 18,000 km to 160,000 km. It ran just as fast as with regular diesel, but with significantly less soot emissions. As for the smell, it depends on whether the car has a catalytic converter and whether it's still working. Mine smelled like french fries only until the catalytic converter was warm. When it was cold, it also produced a bit of blue smoke. I sometimes had the feeling that the injectors were dripping a drop or two of fuel into the cylinders overnight, because it often produced some blue smoke shortly after starting. The oil consumption was approximately 1 liter per 15,000 km.
Regards,

Eike.