2.0 LITER PLUG-IN HYBRID. HEATER HOSES. Upper pipe. HVAC Heater Hose. Pipe that is part of the engine cooling system. PTC Heater. Breather. Connector. Cooler. Coupling. Engine Coolant. Hose and Amplifier; Assembly. HVAC Heater Hose. Return. Water feed. Water manifold.