A decongealing channel for use in a heat exchanger apparatus, including a supersaturated solution contained therein and an actuation component in fluid communication with a lubricating fluid coupled to the decongealing channel. The actuation component is responsive to a change in pressure exerted thereon by the lubricating fluid so as to actuate an exothermic response in the supersaturated solution. The heat exchanger apparatus is disposed in a bypass fan duct of an aircraft engine. The heat exchanger apparatus including a manifold portion, one or more flow through openings extending therethrough the manifold portion to define one or more flow through channels having contained therein the lubricating fluid. In addition, the manifold portion including one or more additional openings extending therethrough to define one or more decongealing channels. Further disclosed is an engine including the heat exchanger apparatus and a method of decongealing a lubricating fluid in the heat exchanger apparatus.