It would help if you said what the problem is. - Thermostats usually either work or don't. If they don't it takes a long time for the engine to get warm, -this has nothing to do with the water pump.
Water pumps sometimes leak, you lose water and can see this in the rad. -there is no repair, -you change it for a new one. -This problem has no similarity to any thermostat problems.
If electric water heater, usually bottom element going bad. Thermostat might be set too high or is going bad.
it is located between the radiator hose going into the water-pump housing.
The engine thermostat, on a 2008 Chevy Impala 3.5 V6, is located on the lower front side of the engine. The thermostat will have a water hose going into the top of it.
could be your thermostat or you have no antifreeze coolant or your water pump is going bad
Low coolant, failed thermostat, missing belt, failed water pump, failed HVAC control, etc
The thermostat controls only the temperature of the water.
The thermostat is inside of the water inlet on top of the motor. Disconnect the top water hose, then unbolt the water inlet. The thermostat can then be changed.
Could be as simple as a stuck closed thermostat or as major as a bad head gasket or worse, a cracked head.
I'm going on the assumption that you have a V6 in which the thermostat is between the two upper timing belt sprockets and just above the water pump. Replace the thermostat with the spring side in the block adn the air bleeder to the top.
Thermostat is located in the aluminum housing attached to the water pump. You can easily find it by following the lower radiator hose out of the radiator and going into this housing. There are two bolts that secure the housing to the water pump that once removed will reveal the thermostat. Make sure that you orient the thermostat with the little jiggly thing at the top and use a new rubber gasket around the perimeter of the new thermostat.
one of the things that could be casing your ovreheating problem is a stuck thermostat. The thermostat stays closed until the engine gets to a certaqin temperature and then opens up to cool the engine. if the thermostat fails to open no coolent gets to the engine therfore causing the engine to overheat. one way to tell if your thermostat is going out is your upper radiator hose where the themostat housing is will be stretched and feel kinda rubbery. hope this helps could also be that your water pump is going and or a broken water pump belt...but id go with the thermostat first.then take it from there.
Remove the top water line from the radiator to the water pump. The thermostat is found there.