The cooling system should be flushed and refilled as recommended. The level, condition, and concentration of the coolant should be checked periodically. (A 50/50 mix of anti-freeze and water is usually recommended.) If you’re doing your own work, allow the radiator to cool down completely before removing the cap. (Newer vehicles have coolant reservoirs.) The tightness and condition of drive belts, clamps, and hoses should be checked by a certified auto technician.