How do you change the thermostat on a fiat palio 16v?

To change the thermostat on a Fiat Palio 16V, start by ensuring the engine is cool and disconnect the negative battery terminal. Drain the coolant from the radiator, then remove the hoses connected to the thermostat housing. Unscrew the housing, take out the old thermostat, install the new one with the correct orientation, and reassemble the housing and hoses. Finally, refill the coolant, reconnect the battery, and check for leaks.