The thermostat is located in the housing where the upper radiator hose connects to the engine.Remove the 2 bolts and remove the thermostat.
For the 2000-3.5L V6 or 3.9L v6 For the 2005- 3.4L V6 or 3.8L V6
The 2000-2005 Chevrolet Impala only came with a 3.4 and 3.8 V6 (6 cylinder) engines. Are you sure that you don't have a Malibu instead? at the emd of the upper rad hose you will find the thermostat housing. Take the 2 bolts out and remove it. When reinstalling it make sure the spring on the thermostat goes toward the engine.
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.
The 3.4 and 3.8 litre V6 engines in a 2000 Chevrolet Impala have a timing CHAIN
On the highway the 3400 V6 will get at least 30 mpg, and the 3800 V6 will get 28mpg. Better depending on how you drive and how much weight you are carrying. The 2000-up Impala gets excellent mileage for a large car.
Either a 3.4 or 3.8 V6
Check
On the 2.5L V6 the thermostat is under the housing that the lower radiator hose hooks to on the engine.
Pointy end up.
follow top radiater hose to it,it is hard to access housing!!! for thermostat, the thermostat is at the end of the lower intake manifold on drivers side of engine.
Left Side of the engine: in the sensor case attached to the vacuum hoses
if its a 3.1 v6 it is located at engine, end of top radiater hose!