A waste heat accumulator/distributor system for use in a vehicle. The system includes an engine coolant loop directing engine coolant through a power plant, a powertrain electronics coolant loop directing electronics coolant through a powertrain electronics system; and a transmission fluid loop directing transmission fluid through a transmission. The system includes a multi-fluid heat exchanger including an engine coolant inlet receiving the engine coolant from the engine coolant loop, an electronics coolant inlet receiving the electronics coolant from the powertrain electronic coolant loop, and a transmission fluid inlet receiving the transmission fluid from the transmission fluid loop; a first valve controllable to cause engine coolant to flow into the engine coolant inlet or to bypass the engine coolant inlet; and a second valve controllable to cause electronics coolant to flow into the electronics coolant inlet or to bypass the electronics coolant inlet.