You all know an engine will be damaged if too hot, and will be inefficient if cold. So we need a Thermostat to keep an engine at profer temperature, by letting or blocking Radiator Coolant flow through.
The thermostat locates inside the Thermostat Housing, while the Thermostat Housing is at the end of Radiator Inlet Hose, and sitting on the upper of Engine Block. Some commerical vehicle or engine has two Thermostats for different Temperature control.
Disconnect the thermostat housing from engine, you will see the thermostat. Perhaps you need to gently pry it up with a flat edge from a knife or screwdriver. Remember to clear the surface of Thermostat housing and engine block before replacing. It's important to replace the gasket together.
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