Hydraulic tools including removable coatings, drilling systems, and methods of making and using hydraulic tools

A method of operating a hydraulic tool, comprising:

• coupling a hydraulic tool to a drill string, the hydraulic tool comprising:
• a stator defining a plurality of lobes;
• a rotor defining at least one lobe and configured to rotate within the stator, the rotor configured to rotate within the stator responsive to fluid flow through the stator;
• at least one of the stator and the rotor comprising a resilient material;
• and
• a removable coating disposed on a surface of at least one of the rotor and the stator, the removable coating having a thickness selected to compensate for at least one of an expected swelling of the resilient material during a drilling operation or an expected contraction of a clearance between the rotor and the stator based on thermal expansion of the rotor and the stator, the removable coating formulated to be removed during operation of the hydraulic tool;
• passing a fluid through the hydraulic tool during rotation of the rotor within the stator;
• and
• removing at least a portion of the removable coating responsive to rotation of the rotor within the stator as a volume of the resilient material increases responsive to contact with the fluid passing through the hydraulic fluid.