The cooling system hoses should be replaced when recommended by the manufacturer or when their technical condition (inspected visually) requires so. The hoses distribute the coolant to the particular elements of the system, such as the thermostat, the radiator and the heater. The coolant (glycol-based) takes the heat produced by the engine and is pumped thorough the hoses into the radiator, which is responsible for decreasing its temperature. After cooling, the coolant is transported back to the engine to decrease its temperature. The cooling system hoses and the radiator are also used to heat the car interior. Damage to any of the hoses may cause the coolant to leak, resulting in engine seizure.