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Discussion Starter #1
So this is going to sound stupid im sure, but should i be running bio diesel on my 2011 jetta tdi, i fuelled up once since ive had it and fuelled up with regular diesel. Does this hurt the engine, lower mpg, or do anything to the vehical.

Thanks,
 

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Let me explain that a little better. Bio has less energy so lower fuel economy. It also washes on the cylinder walls so you get reduced lubrication, more wear, and lower fuel economy.
 

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Biodiesel and 'active' diesel particulate filter regeneration cycles don't work well together and on some vehicles will cause fuel dilution of the lube oil sump.

Watch for an increasing lube oil level.
 

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Discussion Starter #5
Ok so let me get this straight, dont run bio diesel? and im new to the whole diesel thing how do i know if its B5 or greater, when i filled up all it said was diesel on the pump.
 

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It should say on the pump but there are some states that have around B2 in the fuel already, some have B5. Here is some on biodiesel blends: http://www.biodiesel.org/news/bulletin/2011/20110501.htm Minnesota and Oregon have B5 by law. Washington and Pennsylvania both have a B2 requirement in effect

Minnesota is scheduled to have B10 by 2012 and B20 by 2015. It will be interesting to see VW's response to these mandatory blends that are higher than what they have ever approved. It will also be interesting to see if past warranty denials based off B10 will receive compensation.

VW approves up to B5 now and they have never approved more than B5 and probably never will. Supposedly some people are running higher but they are doing oil inspections to make sure the oil doesn't get diluted. Older engines ran fine on B100. The difference is the DPF system and post combustion injection of fuel. The big difference vs. older TDI is the DPF system: http://www.myturbodiesel.com/1000q/DPF-Adblue-FAQ-VW-Audi.htm here is a FAQ on it.
 

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I live in canada, and have called a couple of gas stations and 2 of them said they dont know what diesel fuel they have and have hung up on me, and the other one told me just clear diesel fuel. So im racking my brain to know if im putting the right diesel in.
 

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biodiesel versus diesel

Let me explain that a little better. Bio has less energy so lower fuel economy. It also washes on the cylinder walls so you get reduced lubrication, more wear, and lower fuel economy.
Hello ToeBall. What you are saying runs contrary to what I've been explained prior. My understanding from reading the posts of others was that bio diesel actually improved lubrication. What is your source for the assertion that it reduces lubrication. As for the energy content assertion, what is the basis for this? Not saying that you are incorrect, but would like to know your data sources.

thx,

Dan
 

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Hello ToeBall. What you are saying runs contrary to what I've been explained prior. My understanding from reading the posts of others was that bio diesel actually improved lubrication. What is your source for the assertion that it reduces lubrication. As for the energy content assertion, what is the basis for this? Not saying that you are incorrect, but would like to know your data sources.

thx,

Dan
Actually, the biodiesel does increase lubricity, not lubrication. In the common rail engines, it causes damage by the post combustion injection of more fuel used for the DPF regens. Some of this excess biodiesel makes it past the rings and causes oil dilution, more wear, etc.
 

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Let me explain that a little better. Bio has less energy so lower fuel economy. It also washes on the cylinder walls so you get reduced lubrication, more wear, and lower fuel economy.
this is totally wrong. Biodiesel is a much better lubricant than diesel especially the ULSD now. The main issue with biodiesel is it doesn't burn completly so is leaves a tiny amount that escapes into the engine oil and dilutes it. It does not lube as good as regular oil. Normal diesel does this also, and so with normal oil changes it's not a huge problem. This is alo the main issue with newer diesels with DPF because the biodiesel doesn't burn completely it's more sooty and clogs up the DPF faster. The same reason why you have to run a special 507.00 reduced ash oil.
 

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this is totally wrong. Biodiesel is a much better lubricant than diesel especially the ULSD now. The main issue with biodiesel is it doesn't burn completly so is leaves a tiny amount that escapes into the engine oil and dilutes it. It does not lube as good as regular oil. Normal diesel does this also, and so with normal oil changes it's not a huge problem. This is alo the main issue with newer diesels with DPF because the biodiesel doesn't burn completely it's more sooty and clogs up the DPF faster. The same reason why you have to run a special 507.00 reduced ash oil.
It is a better lubricant than regular diesel fuel. It is not, however as good of a lubricant as motor oil, which is what it's washing from the cylinder walls. It also mixes with the motor oil in the oil pan reducing its lubricity for the rest of the engine. While normal diesel fuel does this as well (as does gasoline) less fuel gets into the oil, hence the reduced oil change interval.

Adding in factors such as DPF loading from oil, while correct, simply complicates the issue even more. I was trying to keep it simple. Other factors which are more of an issue than DPF loading from motor oil including loading from less efficient combustion (which you mentioned) and less efficient active regeneration. All these factors will reduce the life expectancy of the DPF.
 
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