Drain engine coolant
Remove the decorative engine cover
Remove the air filter, air duct, and air inlet hose
Remove the 3 mounting bolts and move the thermostat cover together with the radiator hose to the side as far as the hose will allow
On a 4B11 / 4B12 engine, the third bolt secures the wiring harness retainer connection.
Using your hand to hold the retracted cover together with the radiator hose, remove the thermostat and O-ring.
Install the new thermostat with the air valve at the top
Note:
Make sure that there is no oil on the rubber sealing ring of the thermostat.
Be careful not to bend or scratch the O-ring during installation.
If the rubber ring is damaged, replace the thermostat.
Install the thermostat cover together with the radiator hose into place, tightening the bolts of its fastening to the nominal torque
Note:
Nominal tightening torque of the thermostat cover bolts: 4B11 and 4B12 engines – 24 ± 3 Nm (top and right bolts) / 11 ± 1 Nm (bottom bolt of the ground wire); 6B31 engine – 23 ± 6 Nm.
Reinstall the remaining removed parts in the reverse order to remove.