# The Function and Maintenance Methods of a Forklift Thermostat

The function of the forklift thermostat is to automatically regulate the circulation of coolant in the radiator, keeping the cooling water in the water jacket at a certain temperature. The thermostat is installed in the outlet pipe of the cylinder head and consists of an expandable brass bellows and two water valves, with a low-boiling-point ether solution sealed inside the tube. When the temperature is below 70°C, the valve leading to the radiator is closed, while the opening leading to the water pump is open, allowing the water in the water jacket to flow only through the bypass water port into the pump for small circulation. When the temperature rises above 70°C, the thermostat valve opens, permitting the cooling water in the water jacket to flow through the valve into the radiator for large circulation. Therefore, the thermostat ensures the engine operates at its optimal working temperature. 1. Through forklift engine inspection, if the engine fails to reach the specified temperature within the specified time (10 minutes) after starting, it indicates that the thermostat has been damaged. 2. Remove the thermostat and place it in a container filled with water, then gradually heat it. Use an accurate thermometer to measure the water temperature, and record the temperatures at which the thermostat valve begins to open and is fully open. These temperatures should conform to the scale reading on the upper surface of the thermostat. Generally, a good thermostat should begin to open at 68-72°C and be fully open at 80-83°C. If the thermostat fails to operate properly after the above inspections, it should be replaced.