Where is the thermostat on a 2000 S10 Chevy pickup?

The thermostat on a 2000 Chevy S10 is located at the very back of the engine, on the passenger side. It's usually tucked in pretty tight and requires removing some components to access it. You'll likely need to remove the upper radiator hose to get to it. Because of its location and the potential for needing specialized tools, this is generally a job best left to a mechanic if you aren't experienced working on engines.