Heater hoses and pipes, found within the HVAC system (HVAC > Heater Hoses & Pipes), are critical components for delivering engine coolant to the vehicle's heater core. The heater core acts as a small radiator, warming the air that enters the passenger compartment. These hoses are constructed from reinforced rubber compounds, specifically engineered to withstand the high temperatures and pressures of the engine cooling system. Replacement is often necessary due to cracking, leaking, or deterioration of the rubber over time. Examples in this category include heater hoses for MAN trucks, such as MAN MPN 81.61960-0791, as well as components for Volkswagen and Audi vehicles. Maintaining these parts ensures efficient cabin heating and prevents coolant loss.