What is the main task of the Coolant Pipe in the car cooling system?

The Coolant Pipe ensures that the coolant circulates efficiently between the engine, radiator and other components in the car cooling system, thereby maintaining the normal operating temperature of the engine and preventing overheating. As a channel for the flow of coolant, the Coolant Pipe is responsible for transporting the high-temperature coolant from the engine to the radiator for heat dissipation (through the upper hose), and then returning the cooled liquid to the engine (through the lower hose). For example, when the engine is running and generating high temperatures, the hose guides the heat-absorbing coolant to the radiator, and the heat exchange between the radiator fins and the air is completed. In addition, some hoses (such as heater core hoses) also transport high-temperature coolant to the car's heating system to provide heat for the passenger compartment.
The Coolant Pipe needs to withstand the high temperature in the engine compartment and the pressure of the cooling system. For example, silicone hoses can withstand temperatures up to 177°C, while EPDM rubber hoses are both ozone-resistant and aging-resistant. Additives in the coolant (such as antifreeze, rust inhibitors) and possible oil contamination require the hose material to be chemically stable. EPDM rubber has become the mainstream choice due to its corrosion resistance to coolant. The vibrations generated when the engine is running may cause the connection of metal parts to loosen, but the flexibility of the hose can absorb the vibration and avoid leakage or breakage.
The Coolant Pipe connects the core components such as the radiator, water pump, thermostat, and expansion tank to form a closed-loop system. Connect the engine water outlet to the top of the radiator to deliver high-temperature coolant. Connect the bottom of the radiator to the water pump to return the cooled liquid to the engine. Regulate the coolant flow and release excess liquid through the expansion tank when the pressure is too high.
By controlling the engine temperature, the hose indirectly affects fuel efficiency and emissions. If the hose fails and causes coolant leakage, the engine may damage key components such as the cylinder block and piston due to overheating, or even cause serious failures. For example, when the hose ages and breaks, the coolant quickly loses, and the engine may "pull the cylinder" due to overheating within a few minutes.
Because the hose usually ages from the inside (affected by the electrochemical corrosion of the coolant), it is recommended to replace it every 4-5 years or 80,000-100,000 kilometers, and regularly check the outside for cracks, bulges or softening. Common fault manifestations include coolant leakage, abnormal increase in engine temperature, and failure of the heating system. For example, a leak at a hose connection could cause the coolant level to drop, triggering an alarm on the instrument panel.