From GMC manual:
DURAMAX® B20 Biodiesel Capability
To reduce carbon dioxide emissions and stretch your fuel budget further—without sacrificing vehicle performance—the DURAMAX 6.6L engine is engineered to operate on B20 biodiesel fuel, a mixture of 80% petroleum diesel and 20% biodiesel produced from domestic, renewable resources.
"Next to prayer, fishing is the most personal relationship of man"Calvin Coolidge
"American by Birth, Southern by the Grace of God"Lewis Grizzard
2016 GMC Denali 3500Dually--2017 CC 36CKTS