Bio-diesel / Is it a good or bad thing for the engine ?

Bio helps provide some of the lubricity lost with the switch to ULSD years ago. I have been using it in my diesel pickups for years without trouble and my circa 1995 Deere utility tractor uses it also with no problem. My soon to be delivered 40KW standby generator will also be running a bio blend.

Your biggest issue will be it has higher cloud and gel points than non-bio and vehicles designed for higher concentrations will generally have a larger capacity fuel heater at the filter. Bio diesel is a little better solvent than straight diesel and an older fuel system first introduced to bio will likely need a filter change fairly soon for the first cycle.

You have probably run bio before without knowing it because it has been prevalent in most of the market for over a decade.

I hate "farmer gas" ethanol fuel but I am fine with bio diesel (which also makes far more sense economically and environmentally than the ethanol laced garbage fuel).

You are going to get a LOT of contradictory information and advice here asking that question. I can only tell you that most of what is/will be said is tainted by unsubstantiated opinion.

But I will tell you facts. I have had three diesels, two that were supposed to only use no more than 5% biodiesel, and the third no more than 7%. All three have been run at higher concentrations without incident. One of the 5%ers has 180,000 miles, of which around 100,000 miles was more or less continuously at B20 to B50, with occasional brief periods on B100. At around 125,000 miles the injection pump started leaking and had to be replaced. It should be noted that this seems to have happened to others of its type that have never run biodiesel, so I'm not sure it had anything to do with biodiesel.

The second, another 5%er, ran for around 50,000 miles on B20-B50 without incident. At 150,000 miles, an overheating incident while towing caused a blown head gasket and cracked head, which was replaced. At 200,000 miles, the last being with no biodiesel, the rebuilt head with new valves, dropped an exhaust valve killing the engine. Clearly the biodiesel had nothing to do with the dropped valve.

The third, and newest of them now has 110,000 miles, and though officially limited to B7, has seen an occasional tank of up to B20, without skipping a beat. This vehicle is the only one of the three with a DPF.

There are strongly opinionated people who will insist that a single tank of 5% biodiesel is the reason their radio no longer works. I know this, because I've met them.

Frankly, my own personal experimentation has resulted in my own opinion that use of biodiesel has no untoward consequences for engines, enough so that I don't worry about it at all.

My 6.0 Powerstroke liked running on B10 due to the additional lubricity in the fuel and I actually got better mileage with it than running straight ULSD with a friction modifier. If I remember correctly, that era of Powerstroke was only certified for B5 even though I ran a greater bio mix. My 6.7 Cummins is rated for B20 and I see no difference in performance or mileage between B20 and straight ULSD.

My state (Washington), and probably Oregon also, mandates a minimum of 2% biodiesel. They can add up to 5% of bio and still call it #2 diesel. No getting away from it.

I ran it twice in my 12 CTD. Zero issues. In fact it sounded nicer and seemed to run smoother. I needed some diesel at the coast and the only station in the area was B20 IIRC. I only put in enough to get me to home. The other time was pretty much the same circumstances.

No preference either way but the correct answer is, "Read the owners manual for your vehicle."
It will tell you what you can run.

Thank you all, you guys are teaching me a lot. I am in Oregon, and the button on the pump said S15. Had never seen that before. I have a 2016 Duramax, so I better read the manual. My rig has only 3600 miles on it, and I have changed oil once, but not fuel filter. I better look into it. I need to find out how often the fuel filter needs changed. We got a foot of snow now. I can wait a bit. I don't drive it much right now.

If it comes out of the pump it’s ok in your truck. Nothing to worry about in your sitch.

Durb wrote:
My state (Washington), and probably Oregon also, mandates a minimum of 2% biodiesel. They can add up to 5% of bio and still call it #2 diesel. No getting away from it.

Oregon mandates 5% bio. Many states mandate 2-5% bio diesel. I suspect you would be hard pressed to find many places with NO (0%) biodiesel,

Now biodiesel does have a slightly lower energy content. I say slightly since it is on the order of 1-2% lower. However bio has a higher Cetane rating, and better lubricity.

Personally I run B20 when I can find it, and in oregon B20 is exempt from state fuel tax so often costs less than B5

And on my 04.5 duramax I noticed that with B20 (yes I know they say don't use it in the 04) in cold weather less diesel rattle when cold or accelerating, likely from the higher cetane rating,

T18skyguy wrote:
Thank you all, you guys are teaching me a lot. I am in Oregon, and the button on the pump said S15. Had never seen that before. I have a 2016 Duramax, so I better read the manual. My rig has only 3600 miles on it, and I have changed oil once, but not fuel filter. I better look into it. I need to find out how often the fuel filter needs changed. We got a foot of snow now. I can wait a bit. I don't drive it much right now.

S15 has NOTHING to do with biodiesel. it is the max sulfur content. And that is federally mandated and also mfg require diesels after about early 2000 to only use S15.

Oregon diesel will be 5% Biodiesel unless you fill at a pump that says otherwise, often "up to B20".

And the 2016 duramax manual says you can use B20.

Fuel filter life will show on the DIC. manual states a time duration or when it says 0% whichever is lower.