Where is the thermostat located on a 1991 Chevrolet Cavalier with 2.2 engine?

The thermostat on a 1991 Chevrolet Cavalier with a 2.2L engine is located on the engine, at the lower intake manifold. It's usually housed within a thermostat housing that's bolted to the intake manifold. You'll need to look closely at the engine block near where the upper and lower radiator hoses connect. Access might require removing some components for easier access.