Unplug the cable, which was not earlier removed, on the negative battery terminal. Take out the distributor to get to the housing of the thermostat. To drain the cooling system, loosen the
Radiator cap and open the petcock at the bottom of the radiator and drain the cooling system until the level goes below the thermostat, then close the petcock when the system is adequately cooled. Disconnect the upper radiator hose and fan thermo switch connector and discharge the upper part of the radiator hose into the water outlet. Take out the two housing nuts and then detach the housing to the engine with a rubber mallet in case the housing gasket is sealed. Remove thermostat in the thermostat housing and prior to the installation of the new thermostat, wipe the gasket around surfaces around the water outlet and thermostat housing. Place a thin layer of sealant on both sides of the new gasket, make sure the thermostat goes in the housing, and then install the gasket (printed side towards the thermostat) and the water outlet and loosen the bolts to the recommended torque. Attach the upper radiator hose and clamp the hose firmly making sure that the arrow on the hose fits in the housing tab. Connect the plug of the thermo switch to the connector, fit the distributor and fill the cooling system with the right antifreeze/water mix. Reconnect the battery cable and turn on the engine and then run it with the radiator cap off until the upper radiator hose becomes hot and the thermostat is open. As the engine idles, pour in coolant to the radiator up to the bottom of the filler neck and then put in the radiator cap.