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.
Remove the top water line from the radiator to the water pump. The thermostat is found there.
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.
Could be as simple as a stuck closed thermostat or as major as a bad head gasket or worse, a cracked head.
U take the thermostat out, get a pot of water, put the thermostat in it and start it to boiling. When the water reaches the temp that the thermostat is designed to operate at it should open , if not , it is defective
Drain the water from the cooling system. Remove the water supply line to the thermostat. Remove the thermostat housing bolts. Remove the thermostat. Reverse the process to install the new thermostat.