In four-cylinder engines, the thermostat is installed in the bottom of the
Water Pump affixing and in five-cylinder engines it is located behind the water pump at the left side of the cylinder block. To empty the cooling system, initially empty the cooling system by draining it then unbolt and remove the thermostat cover with care to extract the O-ring. Then remove the thermostat out of its case. To test whether the unit is working, hang it in a container of water using a piece of a string and slowly heating the water, record down what temperatures the thermostat starts to open and also when it opens fully. When the thermostat is not in the water, take it out and make sure that it is fully closed when it is cold; change the thermostat when it does not work as indicated. Wipe the face of the thermostat housing and cover and install the thermostat in the housing, having the arrow on the crosspiece facing out of the engine on four-cylinder motors and down the engine on five-cylinder motors. Install a new O-ring on the thermostat or cover where necessary and install the thermostat cover and torque the bolts to the recommended torque, then fill in the cooling system.