Inside the engine, the fuel and air mixture will explode forcing the piston down, making the motorbike to move forward. Without a doubt, we can say that the lot of heat will be produced in and around the cylinder walls. If too much amount of heat is present in the engine, the components could fatigue and there are chances for piston getting seized inside the cylinder. To take away the heat produced, those cooling fins, engine oil and coolant oil comes into action. Today in market, engine producing more amount of power comes with the liquid cooling system where separate coolant is used to take away the heat produced and where in oil cooled motors, engine oil itself takes care of the heat produced. Liquid cooling system is not like air and oil cooling system. It consists of more components in it and if any one of the component gets failed, the heat produced in the system will not be carried away and it damages the internal components. Today, in this post, we're going to see about some common problems in the liquid cooling system.
Leaks in coolant passage hose
As we know, the coolant will circulate around the cylinder walls to carry away the heat produced. After carrying all the heat, the coolant will flow to the radiator for cooling process. After the temperature of the coolant is reduced in the radiator, those coolant will again travel to the cylinder for carrying the heat again. This process continues until the reduction in overall engine temperature. The coolant circulation will be carried out with the help of hoses connected across the radiator and the engine block. If there's any hole or damage in the hoses, the coolant will leak through that. If there's less or no coolant, the heat produced in the engine will not be carried away and the engine overheats unwantedly. The expansion of coolant during increase in temperature will make the leak even more worse making it to leak faster. So, before every ride, make sure whether there's no coolant leakage and there's sufficient amount of coolant present in the expansion tank.
Coolant pump failure
Impeller will be present inside the coolant pump assembly. In some Yamaha motorbikes, the coolant pump assembly will be present in the head, directly connected to the camshaft. In motorbikes like Pulsar, the pump assembly will be present in right side of the crankcase, driven by the crank itself. In the pump assembly, if any one of the fin in the impeller is damaged, the suction will become low and the coolant circulation will be affected. If this happens, the coolant will not be circulated and this affects the cooling efficiency of the engine. While servicing, coolant pump assembly should be inspected and should be replaced if necessary.
Coolant pump's seal
This seal is the most important one and does the important role of preventing the coolant oil to mix with the motor oil or vice versa. This seal will be present near the impeller. It just looks like a rubber O ring. If this seal is damaged, coolant oil will escape through that and enters the crankcase, mixes with the motor oil. If this happens, the quality of the motor oil will be affected and the lubricating parameter will also be affected. This will also affect the cooling efficiency. Because, as i said, decrease in coolant oil level will affect the amount of heat transferred and the engine will overheat.
Radiator fan not working
This complaint is mostly seen in Bajaj motorbikes. Even though if the thermostat valve is opened, the fan will not be working. In that case, you have to check several things. First one is the radiator fan relay. Check whether the relay is functioning properly. Short or bypass the relay socket with the help of small wire to make sure whether the fan is running. If it runs, there'll be a problem with the relay and there's no problem with the wirings. Check whether the Coolant Temperature Sensor is working fine. In rare cases, the coil assembly in the radiator fan unit will be shorted. In that case, replacing the whole radiator fan assembly with the new one will be the solution.
Thermostat failure
This thermostat valve is responsible for circulating hot coolant to the radiator and cold coolant again back to the coolant jacket around the cylinder walls. If the coolant temperature once reaches a particular temperature, the valve opens and allow the hot coolant to flow to the radiator for cooling process. If this thermostat valve is damaged or not working, the hot coolant remains in the coolant jacket, not taking further more heat produced. This leads to piston seizure and several other problems.
Damaged fins in the radiator
During the circulation process, hot coolant will be flowing through this small fins present in the radiator. If this fins are damaged, the flow will be disturbed. If this fins are damaged badly, the coolant oil will leak through that. That's why, while water washing the motorbike, more care should be given in this part. If water with more force comes into contact with this fins, it'll be damaged and cause many problems.
Radiator guards
Many aftermarket radiator guards are readily available almost for all motorbikes. We have to understand several things. Radiator guards are mostly used for off-road vehicles. During off-roading, there are chances for the radiator getting hit by mud and dust. As we know, if the fins in the radiator is damaged, the cooling efficiency will be decreased and causes many problems. So the radiator guard will be installed in those off-road motorbikes. But today, almost everyone install this radiator guards. After installing it, many tells that their engine overheats. When the vehicle is in running, air will flow across those fins and cools the coolant present inside it. If the guard is present in between the radiator's fins and the air medium, less amount of air only will flow across them therefore decreasing the cooling efficiency.
Leaks in coolant passage hose
As we know, the coolant will circulate around the cylinder walls to carry away the heat produced. After carrying all the heat, the coolant will flow to the radiator for cooling process. After the temperature of the coolant is reduced in the radiator, those coolant will again travel to the cylinder for carrying the heat again. This process continues until the reduction in overall engine temperature. The coolant circulation will be carried out with the help of hoses connected across the radiator and the engine block. If there's any hole or damage in the hoses, the coolant will leak through that. If there's less or no coolant, the heat produced in the engine will not be carried away and the engine overheats unwantedly. The expansion of coolant during increase in temperature will make the leak even more worse making it to leak faster. So, before every ride, make sure whether there's no coolant leakage and there's sufficient amount of coolant present in the expansion tank.
Coolant pump failure
Impeller will be present inside the coolant pump assembly. In some Yamaha motorbikes, the coolant pump assembly will be present in the head, directly connected to the camshaft. In motorbikes like Pulsar, the pump assembly will be present in right side of the crankcase, driven by the crank itself. In the pump assembly, if any one of the fin in the impeller is damaged, the suction will become low and the coolant circulation will be affected. If this happens, the coolant will not be circulated and this affects the cooling efficiency of the engine. While servicing, coolant pump assembly should be inspected and should be replaced if necessary.
Coolant pump's seal
This seal is the most important one and does the important role of preventing the coolant oil to mix with the motor oil or vice versa. This seal will be present near the impeller. It just looks like a rubber O ring. If this seal is damaged, coolant oil will escape through that and enters the crankcase, mixes with the motor oil. If this happens, the quality of the motor oil will be affected and the lubricating parameter will also be affected. This will also affect the cooling efficiency. Because, as i said, decrease in coolant oil level will affect the amount of heat transferred and the engine will overheat.
Radiator fan not working
This complaint is mostly seen in Bajaj motorbikes. Even though if the thermostat valve is opened, the fan will not be working. In that case, you have to check several things. First one is the radiator fan relay. Check whether the relay is functioning properly. Short or bypass the relay socket with the help of small wire to make sure whether the fan is running. If it runs, there'll be a problem with the relay and there's no problem with the wirings. Check whether the Coolant Temperature Sensor is working fine. In rare cases, the coil assembly in the radiator fan unit will be shorted. In that case, replacing the whole radiator fan assembly with the new one will be the solution.
Thermostat failure
This thermostat valve is responsible for circulating hot coolant to the radiator and cold coolant again back to the coolant jacket around the cylinder walls. If the coolant temperature once reaches a particular temperature, the valve opens and allow the hot coolant to flow to the radiator for cooling process. If this thermostat valve is damaged or not working, the hot coolant remains in the coolant jacket, not taking further more heat produced. This leads to piston seizure and several other problems.
Damaged fins in the radiator
During the circulation process, hot coolant will be flowing through this small fins present in the radiator. If this fins are damaged, the flow will be disturbed. If this fins are damaged badly, the coolant oil will leak through that. That's why, while water washing the motorbike, more care should be given in this part. If water with more force comes into contact with this fins, it'll be damaged and cause many problems.
Radiator guards
Many aftermarket radiator guards are readily available almost for all motorbikes. We have to understand several things. Radiator guards are mostly used for off-road vehicles. During off-roading, there are chances for the radiator getting hit by mud and dust. As we know, if the fins in the radiator is damaged, the cooling efficiency will be decreased and causes many problems. So the radiator guard will be installed in those off-road motorbikes. But today, almost everyone install this radiator guards. After installing it, many tells that their engine overheats. When the vehicle is in running, air will flow across those fins and cools the coolant present inside it. If the guard is present in between the radiator's fins and the air medium, less amount of air only will flow across them therefore decreasing the cooling efficiency.