A fuel cooler is located on the left frame rail forward of the DFCM. The black fuel line is used for fuel return
from the engine to the cooler. The gray fuel line returns fuel from the cooler to the DFCM. Depending on the temperature of the fuel from the injectors, the fuel cooler can be used to cool or heat the fuel going back to
the DFCM. The powertrain secondary cooling system provides the coolant for the fuel cooler.
