Thermostat troubles
 

2000, silverado, 4x4 extended cab,133,000 miles

So I just installed a new water pump as my old pump had leaky seals. With the new pump I put a new thermostat in all napa oem parts. All went well the truck fires up and runs as it did before no leaks anywhere. The problem I am having is that my thermostat will not open up. I have brought the engine up to running temps multiple times and to no avail. The hose running from the lower radiator into the thermostat housing is still cold while the heater hoses are both hot as is the tube running from the top of the radiator to the top of the water pump. And the engine will not over heat either according to the temperature gauge. But as I feel the upper radiator hose and the heater hoses they continues to feel hotter and hotter. Am I doing something wrong is their anything wrong or am I just freaking out?

try putting the thermostat in a pot, bring it to a boil and wait for the thermostat to open up, if it does not open up, it's a bad theromstat.

just a tip from past experience