A heat exchanger includes a central spar, a body, and a mounting arm. The central spar is disposed along an axial centerline of the heat exchanger. The body is disposed around the central spar. The body includes an exterior wall and heat exchanger core disposed within the exterior wall and integrally formed with the central spar. The mounting arm is integrally formed with and extends radially from the central spar. The mounting arm extends through a portion of the body and is integrally formed with the central spar via additive manufacturing.