Gas Type by Car: Regular, Premium, Diesel or E85 / Mercedes-Benz / GLCMercedes-Benz GLC Gas type by year YearGas type2027Premium2026Premium2025Premium2024Premium2023Premium2022Premium2021Premium2020Premium2019Premium2018Premium2017Premium2016Premium Source: U.S. EPA / DOE fuel economy data (fueleconomy.gov).