RAM 2500 2020 Owner's Manual page 226

224 STARTING AND OPERATING
Fuel Operating Range
NOTE:
Use "Ultra Low Sulfur Diesel Fuels" ONLY.
*No. 1 Ultra Low Sulfur Diesel Fuel should only
be used where extended arctic conditions
(0°F/-18°C) exist".
Fuel Operating Range Chart
NOTE:
Use of Climatized Ultra Low Sulfur Diesel Fuel

or Number 1 Ultra Low Sulfur Diesel Fuel
results in a noticeable decrease in fuel
economy.
Climatized Ultra Low Sulfur Diesel Fuel is a

blend of Number 2 Ultra Low Sulfur and
Number 1 Ultra Low Sulfur Diesel Fuels
which reduces the temperature at which wax
crystals form in fuel.