Follow the lower radiator hose to the casting covering the thermostat on the front of the motor. This casting is directly underneath the Power Steering pump. There are three bolts holding the casting onto the block. You will need to use a 10-mm wrench to remove the three bolts. Once you remove the casting, you will have access to the thermostat. You may need to use a pair of pliers to remove it from the block. Once it is removed, there will some anti-freeze that will pour out of the block, so be prepared for the spillage.
Before installing the new thermostat, you should clean the surface of the block and the surface of the casting that you removed, to make sure that both surfaces are clean and smooth to ensure a good seal when bolted back together. You should apply a small amount of high-temperature sealant on the surface of the block and follow the instructions on the sealant regarding proper application and drying times. After doing all of the above, you need to look at the new thermostat and find a small metal pin that will wiggle when you shake the thermostat. This is called the "wiggler". It is used as a vent. The thermostat should be installed with this "wiggler" at the top. After installing the thermostat into the block, re-mount the casting over the thermostat and tighten the three bolts evenly to allow the casting to secure flat to the block. Reconnect the hoses and re-fill the cooling system.