An X-ray tube housing is disclosed that has oil channels integrated (e.g., built into) the X-ray tube housing that accommodate a flow of oil through interior spaces of the X-ray tube housing. A first oil channel from a mid-casing portion of the X-ray tube housing to a pump housing inlet is built into the mid-casing portion, and a second oil channel from a pump housing outlet to a heat exchanger located in an anode-side casing is built into the anode-side casing. The integrated oil channels reduce a number of sealing joints, which reduces the opportunities for leaks, and allows an X-ray tube assembly to be assembled with fewer parts.