If the radiator tanks are plastic you will have to replace the radiator.
How do I get my Radiator out of my 06 impala
There is a small brass valve on the top of the thermostat housing where it attaches to the top radiator hose. Loosen it and then fill the radiator until coolant comes out of the valve and then quickly close it. This is only for an impala with the 3.8 liter engine though I believe there are two valves on the 3.4.
should be similar ...... http://www.justanswer.com/car/3trf2-radiator-drain-plug-2003-chevy-impala.html
Through the radiator cap no... But it does allow the antifreeze to come out through the cap if the pressure gets too high.
Front of the engine. Look for the engine end of the lower radiator hose.
If you want to take the condensor off, you need a refrigerant recovery system.
Buy a kit at Wal-Mart or auto parts - comes with instructions fittings and adaptors
The radiator drain is on the bottom of the radiator. It is a small petcock valve.
There is a belt routing schematic on the radiator core support.
Remove the radiator cap from the coolant recovery jug that is located under the hood on the passenger's side.jd
What is the lug pattern on the 2004 impala?
Drain the radiator down 1/2 way. At the engine end of the top radiator hose is the thermostat housing. Remove the housing and install a new thermostat.