Replaced waterpump, still overheating lights comes on

Check to see if there is water in the oil...If there is water in the oil then it could have a head gasket problem..Did you ever replace the thermostat? If it is stuck then it would also cause overheating...Excessive exhaust backpressure because of a clogged catalytic converter could also cause overheating..Also check belt tension and condition. A loose belt that slips may prevent the water pump from circulating coolant fast enough and/or the fan from turning fast for proper cooling...Another thing it could be is a faulty Water pump -- Any wobble in the pump shaft or seepage would call for replacement. In some instances, a pump can cause an engine to overheat if the impeller vanes are badly eroded due to corrosion or if the impeller has come loose from the shaft. The wrong pump may also cause an engine to overheat. Some engines with serpentine drive belts require a special water pump that turns in the opposite direction of those used on the same engine with ordinary V-belts... Also check the Fan -- With mechanical fans, most overheating problems are caused by a faulty fan clutch, though a missing fan shroud can reduce the fan's cooling effectiveness by as much as 50% (depending on the fan's distance from the radiator) which may be enough to cause the engine to overheat in hot weather or when working hard.

I have a 2005 Chevy Impala 3.4L. And the cooling system for this car is terrible. However, I will tell you. If you replace the radiator and thermostat right off. You will save yourself alot of trouble. My mechanic replaced bot for 400.00 and the car has given little trouble until now. But the cooling system if ignored "will" crack the heads and head gaskets on this model.

Take it seriously from the begining. Please let me know if you need more details.

change t stat

Hi,
Did you replace the thermostat? It's inexpensive and easy enough to do. Sometimes they stick and don't allow enough coolant to circulate through the engine.
This would be my first action. Hope this helps you... Good luck!