A gas turbine engine includes a compressor section, a combustor, and a turbine section. A bleed tap taps air from the compressor section through a bleed valve. The bleed valve is selectively opened by a control to dump air from the compressor section to a dump outlet. A heat exchanger duct includes a duct air inlet to cool a fluid in a heat exchanger and a duct air outlet. The dump outlet is within the heat exchanger duct.