[casioqv]

Most of the diesel stations around where I live now only carry 100% renewable diesel, regular diesel is relatively rare. Unlike biodiesel, it is more or less chemically identical to regular diesel fuel, and meets the regular diesel fuel standards, so I'm not concerned about running it.

Most of our engines were spec'd for B5 when first sold, so I wouldn't really trust VW revising this to a higher level after the fact, when it was basically legally necessary for them to do so rather than an engineering decision, or else tell customers they can no longer use pump diesel in places that mandate blends by law.

That said, the pump failures seem to be from lubricity issues, and biodiesel blends massively improve lubricity of diesel fuel, so I would expect them to extend the life of the pump unless the biodiesel isn't really proper spec biodiesel and is contaminated with particles, water, etc. - which is a common issue, especially if it's made from used fryer oils.

My understanding is that the big issue with TDIs and biodiesel is the extra fuel injected during regen diluting the engine oil. I think a deleted TDI would in principle be fine on 100% biodiesel, as long as the fuel quality was high and met biodiesel specs.

 

[alfissimo]

Bio is great for lubricity but if you have a look at the study, it's not good at all for common rail. Plus Bio can vary in quality greatly. Water is the next big culprit of failures. I forgot to add that to the list. One reason why I am opting for a 2µ secondary filter with water separator.


Petroleum Diesel: Conventional (petroleum-based) fossil fuels are made from crude oil — hydrocarbons, organic compounds, and small amounts of metal from millions of years ago. To make fossil-based fuels such as petroleum diesel, crude oil is removed from the ground, pumped into a refinery, and refined through a heat- and pressure-based process called hydrogenation.

Biodiesel: Unlike petroleum diesel, biodiesel does not rely on fossil fuels. Instead, it is made from vegetable oils and/or animal fats, which are renewable. It is also processed differently than petroleum diesel, using a process called transesterification. This process introduces oxygen into the fuel, which can cause issues with freezing temperature, separation during storage, algae growth, and higher emissions. Biodiesel is generally blended with petroleum diesel at a 5% to 20% ratio.


Renewable Diesel: Like biodiesel, renewable diesel is not a fossil fuel. Instead, it is made of nonpetroleum renewable resources such as natural fats, vegetable oils, and greases. “Renewable diesel, much like biodiesel, is derived from waste agricultural products, particularly waste vegetable oils and waste animal fats,” said Allen Schaeffer, executive director of the Diesel Technology Forum. “As long as we grow soybeans and produce livestock, the waste derived after these products have been processed into food can be refined into a clean, low-carbon fuel.”

Renewable diesel differs from biodiesel, however, in how it’s processed. Renewable diesel is processed similar to the way petroleum diesel is produced, which makes it chemically the same as petroleum diesel.

HVOs (EN 15940 standard) are straight chain paraffinic hydrocarbons without sulfur and aromatics. HVOs deliver high energy content, superior cold operability, low pollution that is attributed to its high hydrogen, absence of oxygen and low carbon, respectively. HVOs are a class of renewable diesel that is close to fossil fuel diesel (EN 590 standard), with an exception to its density. Although the HVOs without oxygen content deliver better cold flow properties that is much needed to high performance of fuel injection system, its poor lubricity behavior can have negative impacts on engine components. Poor lubricity by HVOs can be also attributed to the absence of sulfur.

That said, I'd prefer to use Diesel #2 until more long term evidence shows renewable diesel works well with common rail. When I see commercial stations using it I will assume it will be safe. Why? These stations spend a lot to make sure fuels are clean, filters and will not damage expensive diesel engines in trucks and so forth. I am sure it is fine but would like more information on using it in a common rail before switching over as I am all about reducing the carbon footprint.

One drawback of this process is the poor lubricity of newly composed renewable diesel. Considering that sulfur acts as a lubricant in fuel, the low sulfur content in renewable diesel will lead to low lubricity. Additionally, the oxygen-containing components removed during hydrotreating have been studied and proven to significantly reduce wear and improve lubricity to acceptable levels [3]. An effective and reproducible way of measuring the lubricity of diesel fuel is described in the test method ASTM D6079 [4]. By using a High Frequency Reciprocating Rig (HFRR) we can ensure a diesel fuel’s lubricity is within the requirements as per the Standard Specification for Diesel Fuel Oils in ASTM D975 (<520 µm) [5]. The HFRR instrument and the ASTM D6079 test method involves rubbing a metal ball in an oscillating motion against a platform metal disk under known conditions while fully immersed in the sample heated to 60oC. The output value from HFRR testing is the wear scar diameter, measured in microns. The wear scar diameter is observed and measured after a test by looking at the ball under a microscope or digital camera and averaging the width and the length of the small blemish formed during testing. An unadditized renewable diesel sample typically has an HFRR wear scar diameter over 700 μm, which is far above the permissible level in any of the diesel fuel specifications, typically 450 to 520 μm. Therefore, lubricity improver additives are commonly used with renewable diesel [1].

The lubricity of a fluid is often defined as the fluid’s ability to reduce friction between that fluid and the solid surface during motion. Lubricity is a key fuel property due to the potential to increase the longevity of a part as well as ensuring maximum performance of the system. When a fuel’s lubricity value does not conform to regulations, metal parts are likely exposed to each other, resulting in wear or scarring. In the late 2000s, the lubricity of fuels became a controversial topic due to the increased gas emissions. The high sulfur content in petroleum fuels has been identified as a cause for harmful exhaust emissions, which has led to strict regulations on the allotted sulfur content in diesel fuels globally. A strict regulation was placed to keep sulfur content at a low 15 ppm, according to EPA regulations [7]. While sulfur is a pertinent lubricating agent in petroleum products, regulations have prompted the removal of most of the sulfur in refinery processes, resulting in a loss of fuel lubricity. Due to these lubricity challenges, there is a need for continued research on how renewable diesel can be improved to replace the traditional petroleum diesel.

Lubricity Challenges of Renewable Diesel Fuels

The development of renewable sources of fuel has been pivotal in the reduction of greenhouse gas emissions, as the demand for cleaner fuels continues to grow. With the founding and creation of rene...

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Poor Lubricity of renewables. HVOs as renewable diesel fuel

Keep using your lubricity of choice.

 

[quattroluvr]

Agree... there's no "life cycle". They either work or they don't. There is zero in between.

I read a couple reports of low-pressure failure without grenading so your statement isn't totally accurate.

 

[quattroluvr]

Most of the diesel stations around where I live now only carry 100% renewable diesel, regular diesel is relatively rare. Unlike biodiesel, it is more or less chemically identical to regular diesel fuel, and meets the regular diesel fuel standards, so I'm not concerned about running it.

Most of our engines were spec'd for B5 when first sold, so I wouldn't really trust VW revising this to a higher level after the fact, when it was basically legally necessary for them to do so rather than an engineering decision, or else tell customers they can no longer use pump diesel in places that mandate blends by law.

That said, the pump failures seem to be from lubricity issues, and biodiesel blends massively improve lubricity of diesel fuel, so I would expect them to extend the life of the pump unless the biodiesel isn't really proper spec biodiesel and is contaminated with particles, water, etc. - which is a common issue, especially if it's made from used fryer oils.

My understanding is that the big issue with TDIs and biodiesel is the extra fuel injected during regen diluting the engine oil. I think a deleted TDI would in principle be fine on 100% biodiesel, as long as the fuel quality was high and met biodiesel specs.

I put in a quality lubricity additive every tank and biodiesel is fairly rare here.

 

[quattroluvr]

Don't use any sealer on the gaskets. Clean and dry surfaces is all you need. Loctite is not needed on the bolts either. Just torque them to spec. Re-seal the plate between the oil cooler and block also.

There is a plastic coolant flange just behind the oil cooler. The EGR cooler mates to that flange. I'd suggest you replace it.

that plastic coolant valve was the source of the coolant leak in the "V" of the engine. white deposits under the shaft. Got a new one along with everything else new in the V except the oil cooler which has had no failure reports at all that I could find.

 

[SaVAGeSoot]

except the oil cooler which has had no failure reports at all that I could find.

Interesting.... I swear I've read tons of posts on oil cooler leaks.....

 

[volkswagens-for-life]

I read a couple reports of low-pressure failure without grenading so your statement isn't totally accurate.

Low pressure failure - thats a good caveat. Though, a low pressure failure means its going to grenade at any moment.

Interesting.... I swear I've read tons of posts on oil cooler leaks.....

External EGR leaks or leak-down into the cylinders? Nah, never happens.

 

[NTDI]

Dark Side makes a cp3 kit and so does Bobby Singh

Thought that was for Gen 1 Touaregs (T1/T2). Not the T3s.

 

[volkswagens-for-life]

Thought that was for Gen 1 Touaregs (T1/T2). Not the T3s.

Both will absolutely make one for the CATA - I cannot confirm past the CATA though since it never pertained to me

 

[alfissimo]

Thought that was for Gen 1 Touaregs (T1/T2). Not the T3s.

They don't. Not sure I'd buy anything from them again anyway.