Abstract: An engine cooling-passenger heating system is disclosed having an integrated multi-mode valve arrangement which operates in a no-heat mode to bypass all available flow to the passenger heater past the heater for continued circulation without disruption in the engine cooling system and further operates in a heat mode to effect flow through the heater while also being responsive to the pressure drop across the heater above a predetermined value to also simultaneously establish in the heat mode a restricted connection bypassing a portion of the available coolant to the heater to thereby limit the flow through the heater as well as the pressure differential acting thereon.