Audi A6 4B Exhaust Conversion

Hello everyone!

I have a question about chimney renovations.
I've already read quite a few things on this topic here.
"However, I couldn't find anything about retrofitting an Audi A6 2.5L TDI, 180 HP engine, type 4B, manufactured in 04/2001. I also didn't find much useful information online. I spoke to a conversion specialist, and he said he would rather not convert the car. The reason is that the car has a VP44 diesel pump, which he said is quite sensitive. Can anyone tell me more about this? I actually wanted to install a dual-tank system. The conversion specialist mentioned that the pump might not get enough lubrication (running on rapeseed oil) in a dual-tank system and could eventually seize up. Secondly, it seems the pump doesn't like constantly having to draw in the thick rapeseed oil, even with a single-tank system."
What do you think of his statement?


Thank you very much in advance.

Based on experience, the VP 44 has repeatedly encountered problems with PÖl.

Therefore, it is generally not recommended, as the cost of the pump quickly negates any fuel savings.

You can find more information in the specialist forums fmso.de and fmpo.de.

Thank you for the quick response.
Why do many companies then offer conversion kits for using heating oil in the engine?
They probably have absolutely no idea what they're causing with that.
Could a dual-tank system be installed, where the biofuel tank is always mixed with approximately 10-20 liters of diesel?
Would that be a viable alternative?

"It's quite simple: many companies want to make money. First, the pump doesn't immediately break down, and second, nothing is modified on the pump during the conversion to vegetable oil. Therefore, no supplier will admit that a defective pump is due to the vegetable oil conversion (quote: "We didn't touch it")."

10 bis 20 Liter Diesel erhöhen die Viskosität der Mischung extrem, trotzdem ist sie temperaturabhängig. Lies Dich bitte durch die o.a. Foren.

My personal opinion: Don't do it. Look at the prices for a VP44 pump and calculate how far you would have to drive for a broken pump to be worth it, and how long the new one would have to last. Not to mention other things, like the faster carbon buildup in the injectors.

Best regards!

If everything is done correctly, it should last a while. However, given the sensitivity of the VP44 pump, even a single instance of switching back to diesel too late could be the beginning of a future problem.

I drove my AFN 50TKm with a two-tank system, including a heat exchanger and electric heater! This way, I always had a supply temperature of around 60-65 degrees Celsius, which is actually ideal!

In the end, I ran the engine with a 50:50 mixture of fuel and diesel, because the injectors were still getting clogged every 10,000 km! Then, 35,000 km ago, I switched back to the original fuel, because the risk of the piston rings seizing was too high for me.

I mostly drive on the highway, at around 130 km/h.

The pump was perfectly clean inside, but even after 20,000 km without using oil injection above the turning point, there were still noticeable, sticky deposits on the piston rings! It could also be due to the type of oil used...

I started by buying sausages for 59 cents, but now it's almost not worth it anymore at nearly 0.80 euros.

However, the AFN does not have a VP 44 either.

'Is it already confirmed that it has a VP37? I was just generally talking about the boiler operation!'