Genuine OEM Audi HVAC Heater Hose, part number 4F1265371A. This critical component is designed to circulate hot coolant from the engine's cooling system to the vehicle's heater core, enabling the cabin heating function. It is typically located within the engine bay or near the firewall, forming part of the complex HVAC coolant circuit. Weighing approximately 0.098 kg, this hose is constructed from durable, heat-resistant rubber compounds, reinforced to withstand high temperatures and pressures. Choosing a genuine OEM heater hose ensures precise routing, leak-free connections, and long-term resistance to thermal cycling and coolant degradation, vital for reliable climate control.