Where do you find the thermostat on a 1999 Chevrolet Lumina 3.1?
The thermostat on a 1999 Chevrolet Lumina 3.1L is located on the engine, underneath the intake manifold. It's not easily accessible and requires removing parts of the intake system to get to it. This is a job best left to someone experienced in auto repair. You won't just spot it by looking casually under the hood.