For diesel engine vehicles, see "Diesel Fuel Requirements and Fuel System" in the DURAMAX® Diesel manual.

For vehicles with gasoline engines, please read this.

Use of the recommended fuel is an important part of the proper maintenance of this vehicle. To help keep the engine clean and maintain optimum vehicle performance, we recommend the use of gasoline advertised as TOP TIER Detergent Gasoline.

The 8th digit of the Vehicle Identification Number (VIN) shows the code letter or number that identifies the vehicle's engine. The VIN is at the top left of the instrument panel. See Vehicle Identification Number (VIN) .

If the vehicle has the 5.3L V8 engine (VIN Code 4) and the N15 flexible fuel option, you can use either regular unleaded gasoline or ethanol fuel containing up to 85% ethanol (E85). See Fuel E85 (85% Ethanol) . For the 5.3L V8 engine (VIN Code 4) without the N15 option and all other gasoline engines, use only regular unleaded gasoline.