Water pump is leaking on my 2001 Chevy Malibu need instructions on how to relace

Well, a faulty water pump could cause the engine to overheat fairly quickly, but additional pressure in the cooling system is usually caused by a leaking head gasket.

head gasket tail pipe showing white vapor or water coming out at parked running mode

could be leaking while your driving down the road. check the bottom of the hood and see if the cooling pump is spraying the coolant around(the coolant that comes Chevys is sometimes very corosive to the aluminum parts in your coolant system). should be a wet spot by were your belts are if the pump is leaking. try fushing your coolant.

No.

if you dont have a hole in your radiator hose then you have a bad water pump. when they go bad fluid leaks out the front of your motor. best of luck to you.

the water pump has a drain hole that leaks when seal is bad'change water pump

Due to the complexity of the newer cars on the raod today!! what you are experiencing is Normal!!! since the coolant systems on the newer cars run at such a higher pressure and a high Rpm the reserve tank which has it's on drain hose for excessive overflow from the radiator allows the extra high pressure release from the radiator to back flow to the reserve tank and then out the reserve tank overflow hose on to the raod

I will agree with your uncle and say that you should check the water pump. Start the vehicle and look at the water pump. Most water pumps have a "weep hole". If there is coolant coming out of this hole the water pump is not working properly. If not, and if the temperature has been running normally, you may have fixed the problem when you replaced the cap, if the water pump is good and the temp has been running high, then check the thermostat. Hope this helps and good luck.

When they changed the water pump and the leak stopped then the water pump was bad. If they changed the water pump and was still leaking then then it was not the water pump. 
Where is the fluid leaking from, if there is white smoke coming from the tail pipe then good chance is that the head gasket is gone and pull the dip stick out to see if there is antifreeze mixxing with the engine oil.
It's common that the 3.4 V6 has intake manifold gasket go bad and leak. Check all the heater hose first, and try to find out where the leak is coming from.
Good luck and keep me posted, glad to help you as much as i can.

Replace the pump, the front seal and /or bearing is shot.