Biodiesel: Facts & Myths You Need to Know

Hey fellow mechanics,

Now, it seems I, as a 'biodiesel enthusiast,' have also been affected. My ESP (exhaust smoke pre-treatment system) is starting to leak. Specifically, in the area where the cast iron part meets the aluminum part. There's a slight leak there. Not much, but it's enough that it runs down the engine block and drips off at the bottom.
It was discovered today in the workshop. They were actually only supposed to re-tighten the lower engine cover. It had come loose due to contact with a piece of construction debris hidden by grass. And once that part was loose, we discovered the leak.
The car has now run for 96,500 km in 22 months, with approximately 95% of that distance covered using biodiesel. Since it is still under warranty and has less than 100,000 km on the odometer, the workshop wants to make this a warranty repair. Ultimately, the car is approved for biodiesel, and Volkswagen will have to deal with it, even if BOSCH has refused a biodiesel approval (according to the workshop).
Let's see what happens. Has anyone had experience with cases like this before?
Next week, a new pump will be installed.

Greetings.

Eike.

Having your workshop on your side is already a significant advantage.

The back-and-forth between Volkswagen and Bosch regarding approvals is as old as biodiesel itself, and it often ends up with the confused customer bearing the brunt of it.
Auto Bild, Stern TV, and similar publications have all reported on this before.

VW is allowing all TDI engines produced from a certain year (was it 1996 or earlier?) to be converted to biodiesel, but BOSCH is refusing to approve a general approval for such conversions.


Interestingly, the latest TDI engines (e.g., the 2.0 TDI in the Touran) are NO LONGER approved by VW for use in vehicles destined for Bangladesh.

Luckily, I often come to Luxembourg - currently, the price is 64 cents per liter .
I'm driving a DinoDiesel without any shame.

m;

Hello,

eike wrote:

Specifically, it's in the area where the cast iron part connects to the aluminum part.

There, it's leaking out a little.

First of all, my condolences .
If the warranty doesn't cover it: the O-ring that's leaking costs €2 from Bosch. Anyone with some basic mechanical skills can do the repair, as long as they pay attention to a few things.

Best regards, Uli.

Hello Eike,

It's definitely great that the workshop is on your side (and unfortunately, it's a rare occurrence).
Ultimately, the vehicle has been approved for biodiesel, and then VW simply has to comply with that, even if BOSCH refuses to grant a biodiesel approval (according to the workshop).

To my knowledge, there's a catch with those formulations: VW has approved older vehicles for 'standard-compliant' biodiesel. Your problem now is that you didn't fill up with standard-compliant biodiesel.

Reason: There is no biodiesel that complies with established standards. While there is a draft standard, it has not yet been officially approved (at least, not until a year ago).

Therefore, according to Volkswagen, you made a mistake because you used 'non-compliant' biodiesel, and your car is not approved for use with such fuel.

But maybe you'll get lucky, and the workshop will find a way to get it sorted out with VW.

Regards,
Privately, I'm rooting for you.

Uli S. wrote:

If the warranty doesn't cover it: the O-ring that is leaking costs 2€ from Bosch. Any DIY enthusiast can perform the repair if they pay attention to 2-3 things.

Hi Uli,

What are 2-3 things?
Does the wave need to be honed?

Hello Eike,

It's definitely great that the workshop is on your side (and unfortunately, it's something that happens far too rarely).
Ultimately, the vehicle has been approved for biodiesel, and then VW simply has to comply with that, even if BOSCH refuses to grant a biodiesel approval (according to the workshop).

To my knowledge, there's a catch with those formulations: VW has approved older vehicles for 'standard-compliant' biodiesel. Your problem now is that you didn't fill up with standard-compliant biodiesel.

Reason: There is no biodiesel that complies with established standards. While there is a draft standard, it has not yet been officially approved (at least, not until a year ago).

Therefore, according to Volkswagen, you made a mistake because you used 'non-compliant' biodiesel, and your car is not approved for use with such fuel.

But maybe you'll get lucky, and the workshop will find a way to get it sorted out with VW.

Regards,
Privately, someone who is rooting for you.

Hello,

'I would like to quote excerpts from the operating manual, specifically section '3.2 Personenwagen Rat und Tat':'

'The diesel fuel must comply with the DIN 590 standard.'
RME fuel (biodiesel) according to DIN E 51 606.

'If you use fuel that deviates from the standard, the fuel filter may become clogged.'

On all biodiesel pumps where I have previously refueled, there was a round sticker attached that read: BIODIESEL according to DIN E 51 606.
So, I filled up with fuel that met the specifications of VW (Vornorm DIN E 51 606).
VW could have written in the operating manual: 'If you use fuel that deviates from the standard, there is a risk of engine damage (pump damage, leaks, etc.).' However, they did not write that.
Anyone complaining about a clogged filter can be referred to the user manual and instructions. However, if the pump leaks or even breaks down, the responsibility usually cannot be placed on the customer, who has followed the instructions correctly.
Either the vehicle is incompatible with RME and VW must fix the problem, or the fuel deviated so significantly from the standard specified at the filling station that the RME manufacturer is liable.
Is there already a legally binding ruling on this? With all the concern being raised about it, there should be one by now.

Greetings.

Eike.

PS: Since I drive a company car and have my fuel expenses covered, I naturally have copies of all the fuel receipts and can therefore prove where the fuel came from.
All the gas stations where I buy biodiesel use the same biodiesel supplier: Connemann from Leer. And Connemann is a member of the 'Arbeitsgemeinschaft Qualitätssicherung BIODIESEL' (Biodiesel Quality Assurance Association). The fuel should actually be okay.

haehnlein wrote:

If it doesn't work out with the warranty: the O-ring that is leaking costs 2€ at Bosch. Any DIY enthusiast can do the repair if they pay attention to 2-3 things. Uli S. wrote: Hi Uli, What are 2-3 things? Does the wave not need to be honed? Hello Christian, Why is that? The ESP

must be opened while standing upright, that's one thing. Otherwise, all the rollers and axles will get mixed up or fall out when you remove the high-pressure part (distributor head/ "rusty block"). The O-ring itself is quickly replaced, then the small return springs for the sliding sleeve get stuck with grease in the casting, as does the washer on the distributor piston. Insert the large piston return springs (quote from Joachim S.: "so they really exist" ) and hold them in place with your middle fingers. Now, reassemble the high-pressure part (insert the distributor piston into the bore, place the springs over the pins) and screw it in. Done. I did it like this in the spring with a mechanical VE from an AAZ, and it works great. The VP37 is mechanically the same at the bottom, so it should work the same way.

Best regards, Uli.

I'm not sure how VW handles it, but Audi, for example, rejects all warranty or goodwill repairs if biodiesel has been used.

They also wanted to know if our A6 TDI had been fueled with biodiesel... no, it was fueled with gasoline. Well, we have to pay for it ourselves, but Audi isn't contributing anything.

We just had someone whose car couldn't even reach 40,000 km (it was also a 2.5-liter engine), and they were willing to pay for it... we've had 3 inquiries and 3 rejections.

You probably only get a discount when refueling with biodiesel.

If you can provide them with ALL the fuel receipts, showing where the car was refueled, and whether those fuel stations obtained or processed the fuel according to any specific criteria.

Hi,

The new pump has now arrived at my workshop. It will be replaced on Wednesday. Let's see what happens after that.
I will keep you updated...

Greetings.

Eike.

Hey fellow mechanics,

I have now received my electric scooter back from the workshop, with a new motor.
On that occasion, I inquired again to confirm whether it would definitely be covered under warranty, even if it was clearly due to the biodiesel. The answer I received was yes.
Since the car is less than 2 years old and has VW's BD approval, it is a warranty case, without any doubt. According to the workshop, there is no mileage restriction. So, even if the car had 200,000 kilometers on the odometer, it would still be covered by the warranty.
Well, it doesn't matter, since the tank was almost empty anyway, I went to fill it up with biodiesel.

Greetings.

Eike.

Uli S. wrote:

The ESP must be opened while standing upright, that's one thing. Otherwise, all the rollers and axles will get mixed up or fall out when you remove the high-pressure part (distributor head/ "rusty block"). The O-ring itself is quickly replaced, then the small return springs for the sliding sleeve get stuck with grease in the casting, as does the washer on the distributor piston. Insert the large piston return springs (quote from Joachim S.: "so they really exist" ) and hold them in place with your middle fingers. Now, reassemble the high-pressure part (insert the distributor piston into the bore, place the springs over the pins) and screw it in. Done. I did this in the spring with a mechanical VE from an AAZ, and it runs great. The VP37 is mechanically the same at the bottom, so it should work the same way.

Hi Uli,

I thought the Simmerring on the ESP shaft (which is what we're talking about, right?) could be removed without disassembling the pump (if the shaft is still in good condition) . However, Henzo had to hone the drive shaft of my pump back then because it showed signs of wear -> so it had to be disassembled.

Hi,

The new pump has now arrived at my workshop. It will be replaced on Wednesday. Let's see what happens after that.
I will keep you updated...

Greetings.

Eike

Hey fellow mechanics,

The new pump has been installed for a while now. VW covered it under warranty and hasn't charged me anything so far.
Since I installed the new pump, the MFA (Multi Function Display) shows a significantly lower fuel consumption. So, when I last refueled, I also reset the second counter and the odometer, and now I'm comparing the values during refueling.
According to the MFA (Multifunction Display), the average fuel consumption over 940 km was 5.7 l/100km. Since I always fill the tank completely (using a venting trick), I filled it up the same way this time as I did last time, and then I calculated it: 6.5 l/100km .
What am I supposed to say now? Can someone explain why such a large discrepancy has arisen with the new pump? Almost 15% is a significant amount.
It wasn't like that before.

Greetings and happy holidays.

Eike.

It might be related to the start of fuel injection. I once experimented with the start of fuel injection on my 1.6L engine. I noticed higher fuel consumption when setting it earlier (around 5.2 at the ideal mark, compared to about 5.8 when set too early). However, the engine felt more responsive. Have you checked the start of fuel injection using VCDS?

@Eike:

Hopefully, everything will stay sealed now.
The final standard for BD has already been approved. It is called DIN EN 14214 and replaces the preliminary standard DIN E 51606.

It might be related to the start of injection. I also experimented with the start of injection on my 1Z. I noticed higher fuel consumption in the direction of earlier injection (around 5.2 at almost the center mark, compared to about 5.8 with an earlier setting). However, the car felt more agile. Have you checked the start of injection with VAG-COM?

Hello,
Unfortunately, I don't have access to a VAG-com device or an adapter. However, the car hasn't become any more agile. According to the MFA (Multifunction Display), the fuel consumption has decreased. In reality, it doesn't seem like anything has changed (based on my feeling and the range I'm getting per tank of fuel).

Why did your fuel consumption increase with early fuel injection? It has been stated here several times that early fuel injection can reduce fuel consumption, but manufacturers don't implement it because it also increases NOx emissions.

I'm hearing about this new biodiesel standard for the first time here. I'll pay attention to see if the labels on the fuel pumps change as a result.
The most important thing is that this doesn't result in the fuel used not meeting the standard specified in the owner's manual, and therefore all warranties being rejected.

Greetings.

Eike.

@Eike:

Then I'll also learn something new !

http://www.avd.de/presse/pd/2003_pd_kw44_3_06.html
http://www.transportweb.de/news.php/65258,de_nachrichten_tw