Diesel vs Bio-Diesel


Tito's, Tacos and Trails
Supporting Member
May 27, 2019
San Ramon, CA
So I just bought a new Escalade with a Diesel engine, loving it so far. The milage went from around 17 in my 2015 GMC Denali up to 27 in my new Diesel. My question is Bio-Diesel, The owners manual says I can run blends up to 20%. But I am seeing Diesel #2 and then Bio-Diesel that say contains mire than 20%. Why would they sell Bio with more than 20% if the Mfg. say don't run it ?

New to the Diesel engine world, looking for some wisdom from others



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Those stickers are confusing. You don't want to run bio-diesel greater than B20, however "renewable" diesel is chemically the same as petro diesel and is interchangeable with ordinary #2 diesel.

Where the confusion arises is the sticker that reads, "95% Biomass-Based Diesel Blend."

Renewable Diesel (also called R99) is made from fats and oils, such as soybean oil or canola oil, and is processed to be chemically the same as petroleum diesel. It meets the ASTM D975 specification for petroleum in the United States and EN 590 in Europe. It is in fact biomass-based just like bio-diesel but it is NOT biodiesel. In the instance of renewable diesel, it is 95% biomass based, hence the sticker.

Bio-diesel is produced from vegetable oils, yellow grease, used cooking oils, or animal fats. The fuel is produced by transesterification—a process that converts fats and oils into biodiesel and glycerin (a coproduct). It is not chemically the same at petroleum diesel and cannot be used in emissions controlled diesel engines in concentrations greater than B-20. It is bio-mass based to a degree (5-20%), but not 95% as in the case of renewable diesel, so a 95% biomass sticker cannot be referring to bio diesel unless it is a blend of renewable diesel and bio-diesel vs. a blend of petrodiesel and bio-diesel.

Confused? Me too.

I keep my life simple.

If the pump label reads "Renewable" diesel I use it regardless of any "95% biomass" sticker.
If the label reads R99 I use it.
If the pump is marked "#2 Diesel" with no other sticker or if it has a "B-5" sticker I use it.

However, if the pump label reads "B-20" it is not "Renewable" and has too great a bio-diesel concentration for my diesel Sprinter van so I try to avoid it, although a tank or two of B20 won't hurt anything and sometimes that's all there is at truck stops.

If your owner's manual states that your new vehicle can run B20 you are golden. You can burn petro diesel #2, B-5 to B-20 petrodiesel/biodiesel blends, R99, and "renewable" diesel. In other words, pretty much all pump diesel available in the U.S.

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Why would they sell Bio with more than 20% if the Mfg. say don't run it ?

For the same reason we can find ethanol blended gasoline from 0-85%, even when few vehicles are designed to run anything above 15-20%, and older stuff doesn't like ethanol at all, Gov'mint demands.
I learned something new today. There was an outfit in Monterey that sold B99 for a short time before they got shut down. I ran the old MBZ on it a few times.
I understood that in terms of biodiesel:
- Blends of up to 20% are recommended in the owner's manual.
- Due to regional rules and standards, several Bio-Diesel mixes on the market surpass this proportion.
- When setting gasoline blend limitations, manufacturers frequently err on the side of caution.
-For information unique to your vehicle, contact the manufacturer or a Diesel mechanic.
-Connect with other Diesel owners to share your thoughts and experiences.
When you stated contact the Mfg, that's where my information came from, the owners manual. So I'm thinking that if I contact GM they will most likely give me the same answer