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

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.