To replace the water pump, start by disconnecting the negative battery cable and draining the cooling system. For four-cylinder engines, remove the drive belts, pulley, and alternator. Loosen clamps and detach hoses, remove bolts and detach the water pump and housing, clean bolt threads and threaded holes, and separate the water pump from the housing. Apply RTV sealant and install a new O-ring, attach the new pump, and reinstall all removed parts. Place the new gasket on the water pump and install it, then press the pump assembly. Install the pump-to-mounting bolts and refill the cooling system. Install a new O-ring, attach the new pump, and reinstall the drive belt. Run the engine and check for leaks.