Valvoline’s Premium Blue GEO 15W-40 engine oil provides advanced lubrication protection in engines powered by alternative fuels. Premium Blue GEO 15W-40 is recommended for use in urban buses, delivery trucks and other service fleets that are fueled by compressed natural gas, liquefied natural gas or propane. Benefits include reduced ash content, valve recession protection, advanced oxidation control, low oil consumption, piston deposit control, excellent shear stability and enhanced valve train wear protection, according to the company. Premium Blue GEO is a CES 20074-approved engine oil. It can be used in Cummins B, C and ISL, Detroit Diesel, John Deere and Caterpillar natural gas engines. The product comes in totes, drums, pails and a one-gallon jug.