Bio Diesel

[TheKassman]

All the truck stops I pull into only offer Bio Diesel so I have to battle the traffic at the auto pumps which is #2 Diesel. Any body know if I can use Bio Diesel in and older Cummins engine circa 1998? Its a 325hp 6CTA 8.3L

[BFlinn181]

Is it pure biodiesel or B5 or B20? It won't damage your engine, or they wouldn't be selling it to trucks. B100 (100%) biodiesel is much more expensive than a blend of fossil (dino) diesel and biodiesel. You'll hear horror stories of folks getting contaminated biodiesel fuel and all sorts of tall tales. I've never had an issue with any blend typically sold at most pumps for 20 years. When sulfur was reduced from diesel fuel, the fuel lost some of its lubricity properties. Components of diesel engines use the fuel as a lubricant. Biodiesel actually adds lubricating properties to the fuel, so it means less need for additives.

[RVPioneer]

Per Cummins, you can run up to B20. The engine will run hotter, make less power and get fewer mpg. If used on a regular basis they advise changing fuel filters as well as oil and oil filter every 6-8 months rather than annually. It is not the same as #2.



Keep an eye on the condition of your coolant as well.

[Cat]

Bio fuel shouldn't sit more than 6 Months before using it, temperature and humidity and the quality of the bio will affect life, and its more prone grow algae and bacteria. In cold weather it is much more likely to gel.

[BFlinn181]

Originally Posted by Cat

Bio fuel shouldn't sit more than 6 Months before using it, temperature and humidity and the quality of the bio will affect life, and its more prone grow algae and bacteria. In cold weather it is much more likely to gel.

Buying from a high volume station prevents this. Most cold weather stations sell winter blends that reduce chances of gelling. I've never experienced it in even subzero weather starts. The issue happens more often if an RV fills up in a southern station then travels with that fuel to a colder climate. Same thing can happen with LP, they use different blends in different climates.

[PJStough]

Originally Posted by RVPioneer

Per Cummins, you can run up to B20. The engine will run hotter...

Do you know why the engine would run hotter with B20 than with straight dino diesel?


Thanks

[Cat]

Originally Posted by BFlinn181

Buying from a high volume station prevents this. Most cold weather stations sell winter blends that reduce chances of gelling. I've never experienced it in even subzero weather starts. The issue happens more often if an RV fills up in a southern station then travels with that fuel to a colder climate. Same thing can happen with LP, they use different blends in different climates.

Buying from high volume certainly helps, but that doesn't help if you buy a tank of bio diesel and then the motor/trucks sits for long periods of time. The bio fuel is more hygroscopic than regular diesel. Nothing wrong with wrong with bio, but if my MH is going to sit for a period of time, I would make sure its full of regular diesel.

[BFlinn181]

Originally Posted by Cat

Buying from high volume certainly helps, but that doesn't help if you buy a tank of bio diesel and then the motor/trucks sits for long periods of time. The bio fuel is more hygroscopic than regular diesel. Nothing wrong with wrong with bio, but if my MH is going to sit for a period of time, I would make sure its full of regular diesel.

You could just add a biocide to the tank when the RV is stored. I do it to my small gas engines stored over winter. (STA-BIL, not a biocide)

[Cat]

Originally Posted by PJStough

Do you know why the engine would run hotter with B20 than with straight dino diesel?


Thanks

No I don't. I had not heard of temperature differences. Does the engine seem to lug, climb hills at a lower engine RPM, if so that might contribute to the heat loads.

[Cat]

Originally Posted by BFlinn181

You could just add a biocide to the tank when the RV is stored. I do it to my small gas engines stored over winter. (STA-BIL, not a biocide)

Good point. And if you have bio in your tank it be a very smart move to add a biocide. Biocides sometimes can difficult to find and purchase--- truck stops might sell them though.

[BFlinn181]

Low sulfur diesel = 138,490 Btu/gal
B100 biodiesel = 127,960 Btu/gal

That's a 7% change, and that's for diesel vs B100 biodiesel. I don't think you'd notice any difference in B20 and dino diesel.

from: https://www.afdc.energy.gov/fuels/fu...ison_chart.pdf

[RVPioneer]

Originally Posted by PJStough

Do you know why the engine would run hotter with B20 than with straight dino diesel?


Thanks

Nope. Call Cummins.



I'll go with their information and recommendations rather than make assumptions about what it may or may not do.

[DrDaveMA]

While I am nowhere near an expert, or even very knowledgeable but I have heard that there are different lubricant additives in bio vs Dino. I am thinking those differences could explain different operating temperatures. But as suggested it is best to reach out To Cummins.

[grindstone01]

Originally Posted by PJStough

Do you know why the engine would run hotter with B20 than with straight dino diesel?


Thanks

...


Engine temperature should be controlled by the cooling system thermostate, not the fuel.