A thermal management system for a gas turbine engine includes a heat exchanger including a first coolant passage for a first coolant medium and a second coolant passage for a second coolant medium that is different than the first coolant medium. A first hot flow passage is in thermal communication with the first coolant passage. A second hot flow passage is in thermal communication with the second coolant passage all within a common housing. A first valve controls a flow of a hot medium into at least one of the first hot flow passage or the second hot flow passage. A controller configured to operate the first valve to direct the flow of hot medium into one of the first hot flow passage and the second hot flow passage for transferring thermal energy from the flow of hot medium into one of the first coolant medium and the second coolant medium.