Where is thermostat located on a 1999 Dodge Durango 5.2L engine?

The thermostat on a 1999 Dodge Durango 5.2L engine is located on the engine block, at the bottom of the intake manifold. It's usually near the water pump, but not directly on the water pump itself. You'll need to look closely at the area where the intake manifold meets the engine block. Access might require removing some hoses or other components.