Ford E5TZ-8575-C Thermostat

Before assuming the thermostat is to blame, check coolant level, fan operation, and temperature gauge. If engine takes a long time to warm up, thermostat is stuck open. Replace it. If engine runs hot, check upper radiator hose temperature. If hose isn't hot, thermostat is stuck closed. Replace it. Caution: Don't drive without a thermostat. If upper radiator hose is hot, coolant is flowing. Drain radiator below thermostat. Remove coolant outlet elbow bolts, pull elbow away to access thermostat. Remove thermostat and gasket. Disconnect bypass hoses. Remove bypass tube and water outlet housing bolts. Bend radiator hose upward and remove thermostat and gasket. Clean surfaces, coat new gasket with sealer. Install thermostat in elbow, turn to lock. Position elbow against cylinder head and tighten bolts. Coat new gasket with sealer. Position gasket on intake manifold. Install thermostat in manifold. Position water outlet housing against manifold and tighten bolts. Install water bypass line and tighten hose connections. Fill cooling system with coolant. Start engine, check coolant level and leaks.