What sensor bolt into the thermostat houseing on a 2001 oldsmoble alero?

On a 2001 Oldsmobile Alero, the sensor that bolts into the thermostat housing is typically the coolant temperature sensor. This sensor monitors the temperature of the engine coolant and sends this information to the engine control unit (ECU) to help regulate engine performance and emissions. If you're experiencing issues with engine temperature readings, this sensor is a common component to check.