A heat exchanger duct includes a wall having ends spaced along a central axis. An inlet manifold is positioned within a downstream portion of the duct at a radially outward location. An outlet manifold is positioned within an upstream portion of the duct at a radially outward location. At least one of the inlet and outlet manifolds extend at least 10 degrees around the circumference of the duct. A central manifold is disposed between the inlet and outlet manifolds, and radially inwardly of the inlet and outlet manifolds. Heat exchanger entrance elements extend radially inward from the inlet manifold to the central manifold, and heat exchanger exit elements extend radially outward from the central manifold to the outlet manifold. A gas turbine engine is also disclosed.