To change a water pump, switch off the ignition, find the water pump, pressure test the cooling system, drain the system, remove belts, remove the pump, and install a new pump. Close the drain valve, fill the radiator with a mixture of coolant and distilled water, test the pressure of the cooling system, and test the installation.
Turn off the engine, allow the vehicle to cool, open the hood, and locate the radiator and the water pump. Pry off the radiator cap, place a pressure tester on the radiator and, according to the pressure shown on the cap or in the vehicle owner's manual, test the pressure of the cooling system. Check the pump for leaks, and remove the tester. Underneath the radiator, position a drain pan, and unplug the drain valve to drain the cooling system.
Remove the serpentine and drive belts that surround the air conditioning compressor, alternator and pulleys before disconnecting any hoses from the pump. Unsecure the bolts that hold the pump in place, retain them for reuse, and pry out the pump. Scrape the surface where the pump sits with a gasket scraper. Fix a new gasket to the engine, and tightly secure the new pump in place with bolts. Replace the hoses, belts and drain plug.
Mix equal parts of distilled water and coolant, pour the solution into the radiator, and pressure test the cooling system while checking for leaks. Inspect the overflow reservoir, and fill it with coolant. Turn on and idle the engine before replacing the radiator cap. Perform a road test, and check the temperature the gauge, adding coolant if needed.