The car cooling system is an essential structure for maintaining the engine's operating power. At the famous cars of the Kama Automobile Plant, the coolant ranges from 80-120 0 C. Given that the engine temperature reaches 220 0 C, the special importance of the engine cooling system becomes even more clear.
Features and Important Elements
The KAMAZ car, the cooling system of which is practically no different from the classic, works optimally. In case of deviations, the engine of the car faces considerable trouble. The composition of the main elements of the system is almost the same as in a passenger car:
- cooling radiator;
- water pump;
- branch pipes;
- Thermostats
- cooling Fan.
One difference from the cooling system of non-truck vehicles is immediately apparent - the presence of 2 thermostats. This is primarily due to the structural features of the engine. The V-shaped eight has two cylinder heads located at an angle of less than 90 0 (hence the name). The next distinctive feature is the blinds on the cooling radiator. In the cold season, they are in a closed position and provide an opportunity for quick warm-up of the engine.
The cooling system (KAMAZ 740) includes a hydraulic fan clutch. A controlled drive allows you to automatically adjust the fan speed, thereby intensely cooling the engine.
The scheme of the cooling system
The cooling system (KAMAZ 740) has a typical scheme, with the help of which it is easy to imagine and understand the main points of work. The figure clearly shows that the car cooling system is closed with forced circulation of antifreeze. The speed of the movement is dictated by the water pump (30). The coolant first flows into the cavity of the left row of cylinders, and then through the tube into the cavity of the right row of cylinders.
After the fluid passes through the cylinder heads, it naturally heats up. The next element on the way will be the thermostat (17). Here, depending on the degree of heating, the liquid will either go back to the pump (small circle) or to the cooling radiator (10). A radiator (usually 3 or 4 rows) actively cools the antifreeze and completes a large circle, directing coolant to the pump.
The scheme of the cooling system (KAMAZ) is presented in the figure. There is also an expansion tank (21) with a cover (22) and a liquid level control valve (20). The fan assembly with clutch (9) controls the speed and direction of flow of the coolant. It turns on at a temperature of 85 0 C. In general, the antifreeze temperature during engine operation should be maintained in the range of 85-90 0 C. To improve the direction of air flow through the fan, a diffuser is provided. If the temperature of the liquid in the cooling system is exceeded (98 0 ), the indicator lamp on the instrument panel will light up.
Weaknesses in the cooling system
To begin with, we’ll analyze what can happen with a truck’s cooling system. There are actually not so many problems:
- flow;
- overheating of antifreeze;
- hypothermia;
- ingress of cooling fluid into the oil system.
Leak of antifreeze primarily occurs through the connection of the pipes, and last of all from the destruction (cracking) of rubber hoses. Therefore, one of the weak points of the system is the nozzles. KAMAZ, whose cooling system fails, begins to “suffer” and overheat. After all, if the coolant level drops, the overall heating of the system increases. It is not far from overheating here. To eliminate leaks, it is important to tighten everything up and pressure the entire system.
The second weak point is thermostats. In the event of failure of this element, it is possible both to overheat and to subcool the engine. It depends on in which position the valve is stuck. If the thermostat is open, the liquid “walks” in a large circle through the radiator. In the case of an unheated engine, this prevents the engine from heating up. If the shutters are still open, then the engine can be sub-cooled.
If the thermostat is closed, antifreeze does not enter the radiator and heats up quickly enough on a hot engine. For some time the situation was saved by a fan (KAMAZ). The cooling system stops coping and the antifreeze first and then the engine overheats.
The third in a queue of weak points will be a cooling fan with a clutch. If it fails, the system will not pull out on passive cooling through a radiator. If you look after the car and do routine inspections in time with a stretch of "suspicious" places, then you should not expect any problems from the cooling system.
Cooling Radiator (KAMAZ)
Consider all the main components of the cooling system separately. And let's start with the fact that the first thing that catches your eye is the radiator.
The cooling system (KAMAZ 5320) incorporates a 3- or 4-row cooling radiator. It is made according to the classical type and represents:
- lower tank to which the outlet pipe fits;
- central system of tubes placed in several rows;
- upper tank with inlet pipe.
The radiator mount is three-point. On two sides, it is fixed by brackets, which in turn are connected to the frame side members via shock absorbing elements. The lower radiator mount is connected to the cross member No. 1 of the frame.
A feature of the structure of the radiator (KAMAZ) is the presence of blinds. This is a mechanical system of metal plates that blocks access to the air flow through the radiator. The blinds are controlled by a simple cable drive directly from the cab. If the handle is extended, it means that the blinds are closed, and otherwise open. Due to this, in the cold season, the engine warms up faster.
Fan
The cooling fan of the KAMAZ automobile is mounted on the hydraulic coupling shaft and is externally represented by five blades. Depending on the temperature of the motor, the clutch automatically turns on and off. The fan according to these inclusions either works either, or in the case of a non-working fluid coupling passively rotates from the influence of air flow.
For more effective air blowing, the engine cooling system (KAMAZ) has a casing on the fan. It is made of thin metal sheet by stamping. Thanks to him, air effectively enters only the radiator without side suction.
Cooling system fluid coupling
The cooling system device (KAMAZ) incorporates such an important element as a fluid coupling. The main purpose of this device is to transfer torsion from the crankshaft of a car engine to a cooling fan. In the event of a sharp change in the torque of the fluid coupling, it damps the vibrations, and the fan always works smoothly, without jerking.
Structurally, the hydraulic coupling consists of two wheels rotating on a shaft through bearings enclosed in a housing. The number of blades is different: there are 33 on the leader, and 32 on the follower. Between the hydraulic coupling blades there is an internal cavity that is working. It is through the working cavity that the torque is transmitted when it is filled with oil.
For the cooling system fluid coupling to work, it is necessary that the engine oil enters it. This is due to the switch, which has three positions. 3 latches of the switch correspond to three fan operation modes:
- auto;
- constant fan on;
- the fan is completely off, the clutch does not transmit the torque from the crankshaft.
In automatic mode, the cooling system (KAMAZ Euro 2) works according to the scheme developed by the designers. That is, until the coolant temperature is 86 0 , the oil does not enter the working cavity of the fluid coupling and the fan is turned off. And when the temperature rises, the switch opens, and the oil enters the fluid coupling, thereby turning on the fan.
If the clutch switch is faulty (the engine has overheated), it is recommended to set it to the position with the fluid clutch constantly opening. And after troubleshooting, return to automatic mode. For cases when the car overcomes deep fords, the switch position is recommended to be set in the closed state for the coupling.
Water pump
The cooling system (KAMAZ) has another important element - a water pump. Its main function is the circulation of coolant throughout the engine cooling system. Without it, you cannot create a forced flow in the right direction. And in case of failure, the engine will be in question.
Internal working cavities of the pump are reliably protected by sealants. To prevent malfunctions in the pump there is an oiler through which it is convenient to pump lubricant. A sign of filling is a control hole through which excess grease escapes. As a lubricant, the usual “Litol” is used. In order to find out about a leak in the pump housing, there is a special drain hole. If it flows from there, then the seals do not hold anymore and must be replaced.
Thermostats and branch pipes
The pipes of the cooling system (KAMAZ) must be under good supervision. In the case of a leaky connection, it is likely to lose a large amount of coolant and to overheat the engine. Particular attention should be paid to the junction points of the radiator, water pump and thermostats.
Thermostats in the cooling system are responsible for controlling the flow of antifreeze. When the temperature of the liquid rises to 80 0 C, there is a redirection to the radiator, that is, the circulation at the same time begins to go in a "big circle". At the same time, part of the flow continues to flow along the “small circle”. And only at a temperature of 93 ° C the “small circle” valve completely closes, and all the coolant begins to flow through the engine radiator.
Cooling system maintenance
The cooling system (KAMAZ 740) is practically no different from previous models. You should also be aware that for the 740 engine, the prefixes Euro 0, Euro 2, Euro 3 and Euro 4 do not change the cooling system. So, what needs to be done for the best system maintenance?
The very first action that must be performed every day when the car is in operation is to check the tightness of the entire system (monitor for signs of leakage) and add antifreeze to the recommended level. The coolant itself in the summer can be ordinary water, and in the winter - high-quality antifreeze or antifreeze. For operation in harsh areas of the north, a heating system is installed in the cooling system.
Other maintenance activities that are scheduled are:
- checking the tension of the drive belt;
- water pump maintenance (bearing lubrication plus checking and replacing oil seals);
- checking the tension mechanism of the drive belt;
- full pressure testing of the cooling system;
- quality control of antifreeze and its possible replacement;
- flushing the system in case of severe clogging.
Crimping
The cooling system (KAMAZ 65115) must have complete tightness. Visual inspection is good, but may not show places that are about to begin to miss. To identify such weaknesses, it is good to use a pressure gauge and a pump to create pressure.
For pressure testing, it is enough to apply pressure to the upper radiator inlet with a pump, start the engine and watch the pressure gauge. If everything is fine and there are no gaps in the system, the arrow of the device will not change its position. Otherwise, when the arrow starts to fall, all that remains is to find the problem spot.
Coolant replacement
Cases when you need to replace the entire cooling system fluid are not so rare. The easiest option - winter has come, and the system contains plain water. Replacement may also be required if the fluid loses its cooling properties or is heavily contaminated.
The capacity of the cooling system (KAMAZ) is 25 liters. Of these, 18 liters are consumed per water shirt. To replace the fluid, first drain the old one. To do this, open the lower radiator tap, the drain tap at the heat exchanger and pump in the heating system, as well as the fluid supply pipes in the cab heating system. Do not forget to unscrew the cap of the expansion tank.
After the liquid has completely drained, all the taps are closed. And the entire volume of the cooling system (KAMAZ) is poured through an expansion tank. New antifreeze is selected depending on the time of year and vehicle operating conditions. In this case, do not flatter yourself with imported options in beautiful cans. Domestic coolants have exactly the same properties that meet international quality standards.
Flushing the cooling system
There are many ways to flush the cooling system. In case of slight contamination, you can rinse with plain water. To do this, the old coolant is drained, and instead of it, water is poured. The engine starts and warms up at idle. After this, the water is drained, and the entire cycle is repeated several times until completely cleaned.
If the contamination in the system is significant, it is best to use special ready-made flushing. At the same time, there are quick options when washing is simply added to the old antifreeze, and then everything merges. But it is better to use rinsing solutions when the old coolant has already been drained. It should also be borne in mind that for cleaning the water “shirt” of the engine, the cleaning solutions will be different. The radiator of the cooling system should be washed separately for more efficient cleaning. For this, a well-proven 2.5% solution of hydrochloric acid.
From the features of washing, it should be known that the direction of the washing flow should be opposite to the normal course of the coolant. Flushing the system with a stream of water or a chemical solution under pressure will be more effective.
Troubleshooting
The cooling system (KAMAZ 5320) should work without deviations from inspection to inspection. But the cases are different and malfunctions can occur unexpectedly. Knowing the weaknesses of the system will help to quickly identify the problem and solve it on the spot.
The violation of the tightness of the system is solved by finding the place of the leak and, if possible, eliminating it. A visual inspection is often sufficient for this. All joints are checked, water pump, radiator, coupling. It is better to simply replace worn-out nozzles. Radiator leakage can be eliminated by soldering or plugging leaky tubes. The decision to replace the radiator is made individually, because it is quite maintainable and rinses well when removed.
Deterioration or delamination of the drive belt upon detection is best addressed by replacement. If there is a suspicion of poor-quality operation of thermostats, it is convenient to check them by heating the lower tank of the radiator. At a temperature of 85 0 C, that is, when the thermostat valve starts to open, the tank should warm. If this does not happen, then the valve is defective and the thermostat should be replaced.
The cooling system (KAMAZ Euro 2) is no different from its earlier versions and later ones too. The problems that may arise in the cooling system are the same in their symptoms. One of these malfunctions is the ingress of coolant into the lubrication system. It can be detected by descending antifreeze without a trace of leakage. The cause may be worn head gaskets for the cylinder heads, as well as leaks through the seals of the cylinder liners. The problem is solved by replacing worn engine gaskets.
Conclusion
Car care should be regular and comprehensive. None of its systems can have privileges. At the same time, knowledge of the weak points of a particular car helps well. KAMAZ, the cooling system of which does not have visible problems, should still be regularly inspected and have full-fledged maintenance.