A system for quick warm-up of a motor vehicle having an engine, an exhaust system and a passenger cabin includes a heat collector disposed in the exhaust system downstream of the catalytic converter. The system additionally includes a heater core in the passenger cabin. The heater core is in fluid communication with the heat collector for receiving a heated fluid from the heat collector. The system further includes an expansion tank for receiving fluid from the heater core. The expansion tank is located below the heat collector such that fluid drains from the heat collector back to the expansion tank solely under gravitational force. The heat collector may be combined with a resonator or with a muffler. The heater core may be a combined heater core that extracts heat from both the exhaust system and the engine.