To change a radiator hose, drain the radiator, clean the fittings, install a new hose and refill the radiator. Finish by starting the engine, adding water and more fluid if necessary, and replacing the pressure cap.
To drain the radiator, place a bucket under the drain valve, open the valve and allow the coolant to drain out before closing the valve. Remove the clamps at the ends of the hose, and then gently twist the hose to remove it. If the hose begins to leak, make sure to hold it over the bucket. Clean all of the fittings by using a degreaser or clean rag before putting in the new hose.
To install the hose, attach the ends one at a time, and make sure that the hose does not touch the engine or interfere with other parts. If the coolant is clean and new, fill the tank with the old coolant, but if not, refill the tank with an even mix of water and fresh coolant. Start the engine and watch the radiator level, adding more coolant and water until it drops. Replace the pressure cap, and if the engine needs to bleed, follow the instructions in the owner's manual for the vehicle. Before finishing, start the car and check that all of the clamps are tight and that no liquid is leaking.