Presented are oleophilic surface treatments for electric machines, methods for making/using such electric machines, and vehicles employing traction motors having stator windings with oleophilic treatments on select surfaces. An electric machine includes an outer housing with a direct-cooling thermal management system fluidly connected to the housing to circulate thereto a coolant fluid. A stator assembly, which is attached to the housing, includes a stator core with one or more electromagnetic windings mounted to the stator core. A rotor assembly is movably mounted to the hosing adjacent the stator assembly. The rotor assembly includes a rotor core with one or more magnets mounted to the rotor core spaced, e.g., across an air gap, from the winding(s). Select components of the stator assembly have a target surface with an oleophilic surface treatment that enlarges the target surface's wetted area and increases a coolant mass of the coolant fluid contacting the target surface.