1989 Toyota Tercel location of thermostat

Well first of all you locate athe thermostat housing it should be at the end of the top radiator hose on the engine the housing usually is held on by two bolts. Remove those bots they should be a 13 or 14 mm socket or wrench remove the housing and expose the thermostat remove the old one and replace it with the new one remember to put it in the same way you took it out. Then u clean the hosuing where the old gasket sat get that clean and the space where it sits on the intake manifold after you get that all clean there cant be any old gasket on the housing and intake surfaces finaly you put the gasket in place and bold back down or if you dont have a gasket high temp silicone can be used as a substitute get that alll tightened down and you should be ready to go