Chevrolet: over haeting, coolant pump, water coolant

Question
2005 chevy impala took in for over heating they replaced water pump thermostat intake gasket and it is still over heating It seems that the water is backing up through the over flow bottle help?

Answer

Engine Cooling Diagram Hello Randy,

I've attached a diagram of the cooling system that cars use. Here is the key for that diagram:

Brown: Radiator
Dark Blue: Engine
Light Blue: Cool Coolant
Red: Hot Coolant
Purple: Radiator Fan
Pink: Thermostat/Coolant Flow Valve
Green: Water/Coolant Pump

The important part that I want you to focus on is the pink part. This is how it works:
There is a copper core that mostly blocks the flow of coolant. That part is the valve. When the engine heats up, the coolant to this part becomes hotter, heating the copper core, and causing it to expand, which pushes the core away from the hole in the part. Flow increases, therefore the increased coolant keeps the engine at a safe temperature. If this part is damaged, not enough coolant can flow to the engine, causing it to overheat. As the engine gets hotter, it demands more coolant, but the coolant isn't getting there; it's backing up through the line. You may have a clogged or damaged thermostat.