i hav 2000 impala

ist thing:the brass water sensor that tells the cooling fans is probably toasted.There is mercury sealed inside.When you overheat real bad the sensor is ruined.You might have been lucky not to blow the headgaskets.Put a new or rebuilt W/P on put coolant in, and test it.Check the dipstick make sure there is no water in the oil.If the oil is okay,you may have really been lucky this time.

Check the oil dipstick. If it is milky in color, you have water leaking intothe motor perhaps through a blown head gasket. Check under the car, is there water and or oil leaking out? If so, front or back of the block. Your first thing to do is find the reason for the water leak, then see if it is going into the heads. Pull and clean the plugs, if they are getting wet, they may be shorting out and covered in carbon and stuff/not firing. Check to see if you have any leaks in the fuel system, cracked or melted hose, or vacuum leak. Sounds like the water leak is causing a lot of problems.