I would like to change the water pump myself but do not have a repair manual.
Do you have the 3.4 or the 3.8? Oh well. No one bothers to give that sort of vital information on here... Don't forget to buy RTV when you go buy the pump. Anyway, the 3.4: To Remove: Drain the cooling system. Remove the drive belt guard if equipped. Loosen the water pump pulley bolts. Remove or disconnect the following: Drive belt. Water pump pulley bolts and pulley. Water pump bolts, pump and gasket. Clean the water pump mating surfaces. To Install: Install or connect the following: Water pump gasket and pump. Water pump bolts. Tighten the water pump bolts to 10 Nm (89 inch lbs.) Water pump pulley and bolt until snug. Drive belt. Tighten the water pump pulley bolts to 25 Nm (18 ft. Lbs.). If removed, install the drive belt guard. Fill the cooling system. Inspect for leaks. For the 3.8: To Remove: Drain the cooling system. Loosen the water pump pulley bolts. Remove or disconnect the following: Drive belt. Water pump pulley bolts. Water pump pulley. Power steering pump and reposition. Water pump bolts. Water pump. Water pump gasket. Clean and inspect the water pump mating surfaces. To Install: Install or connect the following: Water pump gasket. Water pump. Tighten the long water pump bolts to 34 Nm (25 ft. Lbs.) Tighten the short water pump bolts to 22 Nm (16 ft. Lbs.) Water pump pulley. Water pump pulley bolts. Tighten the bolts to 13 Nm (115 inch lbs.) Power steering pump. Drive belt. Fill the cooling system. You're lookin' at eight bolts on the pump in most vehicles your make/model.
For the best answers, search on this site https://shorturl.im/avT4K More than you can afford. It's got dual overhead camshafts and the water pump is in with the timing if I'm not mistaking. Because of this, you have to disassemble the entire front part of the engine. You also have to bring it to top dead center, mark the camshafts, remove the timing belt, and a whole lot of other stuff that you just don't want to mess with.
2000 Chevy Impala Water Pump
Im guessing you have the 3.4 liter engine. You will need to remove the pulley bolts first 10mm, then pull off the pulley and the belt. there should be a few 10mm bolts holding the water pump on, remove them and scrape off the old gasket with a scraper and then clean the rest up with some fine grit sandpaper. Don't scrub one area for too long because the surface is soft aluminum. you will need to spray some brake clean on a rag and clean up the surface so there is no coolant or dirt on it. Now put the new gasket on the new pump and put a thin layer of silicone on the side of the gasket that is going to mate with the engine block. Do not put silicone on both sides of the gasket. Make sure to note wich way you took the old pump out because it only goes in one way and torque down the bolts so they are snug, don't overtorque or you will strip the aluminum. Now you will need a half inch rachet to pull back the belt tensioner to be able to put the belt back on. There should be a picture of how the belt is routed somewhere under the hood. Don't forget to buy Dexcool (Red Antifreeze) Make sure you don't mix it with the green antifreeze. Good Luck
