The number of malfunctions caused by high water temperature in locomotive engines will increase. In general, high water temperature is often affected by factors such as loose fan belts, clogged cooling fins in the cooling water tank due to dust and debris, clogged cooling cores in the water tank, failure of the thermostat, and water pump failure. Among them, faults caused by the first three factors can be judged through visual inspection, while the latter two factors require certain experience for accurate judgment. How to determine the malfunction of the thermostat?
1、 Check after starting the engine. Open the water inlet cover of the cooling water tank. If there is water flow in the cooling water chamber of the cooling water tank, it indicates that the thermostat is damaged or there is a foreign object stuck between the main valve. When checking, the thermostat can be placed in hot water above 80 ℃, and after the main valve is raised, the main valve can be opened to remove foreign objects between the valves. If the main valve cannot be opened, the thermostat should be replaced because when the water temperature is below 70 ℃, the ether or paraffin in the expansion cylinder of the thermostat is in a contracted state, the main valve is closed, and the cooling water only circulates in a small and medium-sized state in the engine water jacket. The passage through the water tank is closed by the main valve of the thermostat. When the water temperature reaches 80 ℃, the main valve of the thermostat opens and connects the water path to the water tank.
2、 Inspection of the engine after a period of operation. When the water temperature gauge indicates below 70 ℃ (can be tested with a water temperature gauge, the same below), if there is water flowing at the inlet pipe of the radiator in the water tank, the hot water temperature can cause the cooling water to circulate too early, and the main valve of the thermostat may fail to close tightly.
When the water temperature exceeds 80 ℃, the ether or paraffin in the expansion cylinder expands, the main valve gradually opens, and the cooling water begins to circulate. The circulating water in the radiator of the water tank begins to flow, and the flowing water can be seen through the water tank cover. The thermostat works normally, otherwise it needs to be replaced.
3、 The method of observing the water temperature gauge. 1. Observe the dynamics of the water temperature gauge pointer. When the water temperature is below 80 ℃, observe the water temperature gauge. In the early stages of engine operation, the pointer on the water temperature gauge rises rapidly. When the water temperature exceeds 80 ℃, the movement speed of the water temperature gauge pointer slows down, and the thermostat works normally. If the water temperature keeps rising rapidly, and when the pressure in the water tank reaches a certain level, boiling water suddenly overflows, it indicates that the main valve is stuck or the thermostat is malfunctioning, and needs to be replaced. 2. Feel the water temperature. When the water temperature gauge indicates 70 ℃ to 80 ℃, open the cooling water tank cover and the drain switch at the outlet, feel the water temperature by hand. If both are hot, it indicates that the thermostat is working properly. If the water temperature at the water inlet of the cooling water tank is low, it indicates that the main valve of the thermostat cannot be opened or fully opened. At this time, the thermostat needs to be replaced.
