Only the Mitsubishi radiator and coolant hoses can provide the necessary pathway for the coolant to travel from the hot engine to the radiator so a constant temperature in your engine can be maintained. These Mitsubishi engine components are made out of a reinforced polymer that is flexible and have the ability to withstand the temperature variations the coolant undergoes during the normal operations of your vehicle. The identification of one of these Mitsubishi radiator or coolant hoses is done by knowing their placement on your cooling system. The upper hose is connected to the thermostat housing on the engine and the upper radiator inlet. The lower hose is connected to the lower port on the radiator and the water pump inlet. Between both radiator hoses, it is the upper hose that handles the hottest coolant. This is since it is located at the coolant exit port on the engine while it is traveling to the radiator to be cooled down. Because of this, the radiator hose is usually the one which experiences the most stress from the variation in heat the engine is generating. This stress can be seen by the expansion in the circumference of the polymer hose when it becomes worn. This same condition can occur on either coolant hose since this is a closed loop system and both are exposed to temperature extremes when operating on your Mitsubishi. In this thinning wall of the hose where a pin hole size leak will develop in time. The replacement of either radiator hose should be accompanied by the replacement other hose on your Mitsubishi. This is should be done since both houses have experienced close to the same conditions and will be similar in their wear.