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What are the common faults of the cooling system of Cummins diesel generator sets?

May 17, 2022
As an auxiliary system of diesel generator, the cooling system of Cummins diesel generator set plays an important role in ensuring the normal operation of the engine. It can keep the generator within a proper temperature range under all working conditions. Once the cooling system of Cummins diesel generator set fails, it will cause the unit to fail to operate normally, and even cause serious damage to the unit. Users must pay attention. In this article, the Cummins generator manufacturer will introduce the common faults of the cooling system and the inspection and judgment methods in detail.
1. The amount of circulating water is scarce
Generally, the reason why the cooling effect of Cummins diesel engine is not good is because the amount of cooling water is scarce, and the inability to continuously cool the diesel engine with cooling water will cause it to continuously heat up; the overheating of the diesel engine is because the temperature of these media is too high. When the mechanical properties such as strength and toughness cannot meet the standards, the cylinder head, cylinder liner, piston assembly and valve are mainly subject to a large thermal load, which increases the deformation of the parts, reduces the matching gap between the parts, accelerates the wear of the parts, and even occurs. Cracks, the phenomenon of parts stuck.
Oil that is too hot causes the oil to deteriorate and its viscosity to decrease. The parts that need to be lubricated inside the Cummins diesel engine cannot be effectively lubricated, resulting in abnormal wear. In addition, when the temperature of the diesel engine is too high, its combustion efficiency is reduced, causing the fuel injection nozzle to not work effectively and damage the fuel injection nozzle.
Check Judgment:
1) Before starting the Cummins diesel generator, carefully check whether the coolant meets the requirements;
 2) When the Cummins diesel generator is running, pay attention to check whether there is leakage of the coolant, such as the radiator, water pump, cylinder block, heater water tank, water pipe, as well as the rubber connecting hose and the water drain switch.
2. The pump water supply efficiency is low
 The abnormal operation of the water pump causes the water pressure to not meet the normal requirements, and also reduces the flow of the cooling circulating water. The flow of circulating cooling water is provided by the energy provided by the operation of the water pump. The water pump continuously presses the cooling water to the radiator for cooling, and the cooled water is sent to the engine water jacket to cool the engine. When the water pump works abnormally, the pump energy provided by the water pump is not enough to press the cooling water into the system in time, resulting in a decrease in the circulating water flow in the cooling system, resulting in poor heat dissipation effect of the system, resulting in excessive cooling water temperature.
Check and judge: Hold the water outlet pipe connected to the radiator with your hand, from idle speed to high speed, if you feel that the flow of circulating water continues to increase, it is considered that the water pump is operating normally. Otherwise, it means that the pump is abnormal and should be repaired.
3. The pipeline of the circulation system is fouled and blocked
Circulation system pipeline scaling is mainly concentrated in the radiator, cylinder, water jacket. When the deposited scale accumulates too much, it will cause the cooling water heat dissipation function to decline, resulting in an increase in the water temperature. The main components of scale are calcium carbonate and magnesium carbonate, which have poor heat transfer ability. Scale deposits adhere to the circulation system, which seriously affects the heat dissipation in the engine. If the situation is serious, the circulating pipeline is blocked, the circulating water volume is blocked, the ability to absorb heat is reduced, and the temperature of the cooling water is too high. Especially when the added water is hard water containing a large amount of calcium and magnesium ions, it will cause the pipeline to block and make the cooling circulation system work abnormally.
4. Thermostat failure
The thermostat is a valve that controls the flow path of the engine coolant and belongs to an automatic temperature adjustment device. The thermostat is installed in the combustion chamber of the engine to control the temperature of the combustion chamber.
The thermostat must be at the specified temperature, fully open helps with small cycles, if there is no thermostat, the coolant cannot maintain the circulating temperature and a low temperature alarm may be generated. In order to ensure that the engine can reach the normal working temperature as soon as possible after starting, the engine uses a thermostat to automatically control the circulation of the cooling water. When the temperature is higher than the normal working temperature, the main valve of the thermostat is opened, so that the circulating cooling water flows through the radiator to dissipate heat. When the thermostat is damaged, the main valve cannot be opened normally, and the cooling circulating water cannot flow into the radiator for heat dissipation. The local small circulation causes the water temperature to be too high.
Inspection and judgment: in the early stage of engine operation, the temperature of the circulating water heats up quickly; when the water temperature value on the control panel indicates 80°C, the temperature rise rate slows down, and after 30 minutes of operation, when the water temperature value is basically around 82°C, it is determined that the thermostat works normally. On the contrary, when the water temperature keeps rising after rising to 80°C, the heating rate is very fast. When the water pressure in the circulation system reaches a certain level, the boiling water suddenly overflows, indicating that the main valve is stuck and suddenly opens.
When the water temperature gauge indicates 70°C-80°C, open the radiator cover and the radiator drain switch, and feel the water temperature by hand. If both are hot, it means that the thermostat is working normally; if the water temperature at the radiator water inlet is low, and the radiator is filled If there is no water flowing out or little flowing water at the water inlet pipe of the chamber, it means that the main valve of the thermostat cannot be opened.
5. The fan belt slips, cracks or the fan blade is damaged
Long-term operation will cause the fan belt of the Cummins generator set to slip, the speed of the water pump will decrease, and the water temperature of the cooling system will be too high.
Check fan belt. When the belt is too loose, it should be adjusted; if the belt is severely worn or broken, it should be replaced immediately; if there are two belts and only one of them is damaged, two new belts must be replaced at the same time, not one old and one new. Use together, otherwise the service life of the new belt will be greatly shortened.