Do some of you think the manufacture of the engine in your truck just pulls the % of safe biodiesel out of their tail pipe?
I think some of you think the manufacture put 5%, 10%, 15%, 20% up on a dart board and throw darts at the board and where ever the dart sticks they write that down in the manual as a safe % to run in your engine. :R
Look; manufactures do a lot of testing of the fuel systems that go on their engines. Manufactures want to say you can run any amount of bio in their engines. They can't, because the testing they have done proves it's not a good idea to say that.
Many people have said they have run 20% or whatever % in their engines that mandate 5%. They also say, see, nothing happened to my engine so it must ok to do it. What they don't know is the damage is cumulative. Most will sell their trucks long before the damage shows up. Some won't.
Bio is also insidious because it is not only hydroscopic, it can hold water in suspension. With #2 water almost immediately falls out of suspension. Not true with bio. It loves to hide water among it.
Nothing wrong with small percentages of bio in diesel. But as the % climbs so do the risks and the manufactures know this through ridged testing.
It's best to follow manufactures specs. They know a lot more about your engine than the politicians that mandate the % of biodiesel in fuels.