A thermostatic element inside a housing on the engine actuates the thermostat, which is a restriction valve. It opens and closes to regulate coolant flow at predetermined temperatures, thereby enabling either engine warm-up or cooling. Disconnect the negative battery cable and remove the air cleaner so you can get at the thermostat with ease. Find a suitable container and drain the coolant into it. Remove the thermostat housing bolts and disconnect upper radiator hose from it. At this point, lift up the housing hence exposing the thermostat while considering where it was located previously for later replacement. Clean both surfaces of gaskets on housing and engine body. Insert RTV or equivalent sealer and put the thermostat onto its space properly. With new gasket, fit housing on with correct tightening of bolts. If necessary, re-attach alternator brace and TVS switch plus vacuum hoses as well. Make sure that upper radiator hose is securely attached. Reconnect negative battery cable then use right coolant mixture to fill radiator. Start engine; if necessary pour more coolant into system hereafter. Finally put back radiator cap matching arrows on it with overflow hose.