KAMAZ, cooling system: device and repair

The car cooling system is the most important structure for maintaining the working power of the engine. The famous car of the Kama Automobile Plant has a cooling fluid in the range of 80-120 ⁰ C. Considering that the temperature of the engine reaches 220 ⁰ C, the special importance of the engine cooling system becomes even clearer .

Features and important elements

The KAMAZ car, the cooling system of which practically does not differ from the classical one, works optimally. In the event of deviations from the engine, cars are in serious trouble. The composition of the basic elements of the system is almost the same as that of a passenger car:

• Cooling radiator;
• water pump;
• Branch pipes;
• Thermostats;
• cooling Fan.

One difference from the cooling system is not cargo motor vehicles can be seen immediately - the presence of 2 thermostats. This is due primarily to the peculiarity of the engine structure. The V-shaped figure-eight has two heads of the block of the cylinders located at an angle less than 90 ⁰ (hence the name). The next distinctive feature is the shutters on the cooling radiator. In the cold season they are in the closed position and allow quick warming up of the engine.

The cooling system (KAMAZ 740) has a hydraulic fan clutch. The controlled drive allows to automatically adjust the fan speed, thereby intensively cooling the engine.

Cooling system operation diagram

The cooling system (KAMAZ 740) has a typical scheme, through 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 driving speed is dictated by the water pump (30). Cooling fluid first flows into the cavity of the left bank of the cylinder, and then through the tube into the cavity of the right row of cylinders.

After the liquid passes through the heads of the cylinder blocks, it will naturally heat up. The next element on the way is the thermostat (17). Here, depending on the degree of heating, the liquid will go either back to the pump (small circle) or to the cooling radiator (10). The radiator (usually 3 or 4 rows) actively cools the antifreeze and completes a large circle, directing the coolant to the pump.

The scheme of the cooling system (KAMAZ) is shown in the figure. There is also an expansion tank (21) with a cover (22) and a liquid level control (20). The fan assembly with the clutch (9) controls the speed and direction of the coolant flow. It is switched on at a temperature of 85 ^° C. In general, the temperature of the antifreeze during engine operation must be maintained in the range of 85-90 ^° C. To improve the direction of air flow through the fan, a diffuser is provided. If the temperature of the liquid is exceeded in the cooling system (98 ^° C), the control lamp on the instrument panel will light up.

Weak points of the cooling system

First of all, we'll figure out what can happen with the truck's cooling system. There really are not so many problems:

• flow;
• Overheating of antifreeze;
• Supercooling;
• The cooling liquid enters the oil system.

The leak of antifreeze primarily occurs through the connections of the nozzles, and, lastly, from the destruction (cracking) of the rubber hoses. Therefore one of the weaknesses of the system is the branch pipes. KAMAZ, whose cooling system malfunctions, begins to "suffer" and overheat. After all, if the coolant level drops, the total heating of the system increases. It's not far from overheating. To eliminate leaks, it is important to carefully tighten and press the entire system.

The second weak point can be determined by thermostats. In the event of failure of this element, it is possible both to overheat and supercool the engine. This depends on the position in which the valve jams. If the thermostat is open, the liquid "walks" through a large circle through the radiator. In the case of a non-heated motor this does not allow the engine to heat up. If, in addition, the blinds are open, the engine can be supercooled.

If the thermostat is closed, the antifreeze does not enter the radiator and quickly heats up on the hot engine. For some time the situation is saved by a fan (KAMAZ). The cooling system stops cope and overheats first the antifreeze, and then the engine.

The third in the queue of weaknesses will be a cooling fan with a clutch. If it fails, the system will not pull through passive cooling through the radiator. If you look after the car and make timely checks with the broaching of "suspicious" places, then no problems with the cooling system should be expected.

Radiator cooling (KAMAZ)

Consider all the main components of the cooling system separately. And let's start with what is first of all striking - the radiator.

The cooling system (KAMAZ 5320) has in its composition a 3 or 4-row cooling radiator. It is made according to the classical type and is:

• The lower tank, to which the outlet pipe fits;
• Central system of tubes placed in several rows;
• Upper reservoir with inlet branch pipe.

Mounting the radiator three-point. On the two sides, it is fixed by brackets, which in turn are connected through the cushioning elements to the frame spars. The bottom mounting of the radiator is connected to the crossbar 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 flow of air through the radiator. The blinds are controlled by a simple cable-driven drive directly from the cab. If the handle is extended, then the blinds are closed, otherwise they are open. Thanks to this, in the cold season the engine warms up more quickly.

Fan

The cooling fan of the KAMAZ vehicle is installed on the shaft of the hydraulic coupling and is externally represented by five blades. Depending on the engine temperature, the clutch is automatically turned on and off. The fan according to these inclusions either works either, or in the case of an inactive hydraulic coupling, it is passively rotated from the effect of the air flow.

For more effective air blowing, the engine cooling system (KAMAZ) has a casing on the fan. It is made of a thin metal sheet by stamping. Thanks to it, the air flows efficiently only to the radiator without side suction.

Cooling system clutch

The device of the cooling system (KAMAZ) has in its composition such an important element as a hydraulic coupling. The main purpose of this device is the transfer of torsion from the engine's crankshaft to the cooling fan. In the event of a sudden change in torque, the hydraulic coupling extinguishes vibrations, and the fan always runs smoothly, without jerking.

Structurally, the hydraulic coupling consists of two wheels, rotating on the shaft, through the bearings enclosed in the housing. The number of blades is different: on the leading one there are 33, and on the leading one - 32. There is an inner cavity between the hydro-coupling blades, which is a working cavity. It is through the working cavity that torque is transmitted when it is filled with oil.

In order for the hydraulic coupling of the cooling system to work, it is necessary that the engine oil is supplied to it. This is due to a switch that has three positions. 3 fixing of the switch correspond to three modes of the fan operation:

• auto;
• Constant fan activation;
• The fan is completely off, the clutch does not transmit the torque from the crankshaft.

In the automatic mode, the cooling system (KAMAZ Euro 2) operates according to the scheme developed by the designers. That is, up to the temperature of the coolant 86 ⁰ C, the oil does not enter the working cavity of the hydraulic coupling and the fan is switched off. And when the temperature rises, the switch opens and the oil enters the hydraulic coupling, thereby including the fan.

If the clutch switch is faulty (the motor has overheated), it is recommended to install it in a position with a permanent opening of the clutch. And after troubleshooting, return to automatic mode. For cases when the car overcomes deep fords, it is recommended to place the switch position in the closed state for the coupling.

Water pump

The cooling system (KAMAZ) has one more important element - a water pump. Its main function is the circulation of the cooling liquid throughout the engine cooling system. Without it, you can not create a forced flow in the right direction. And if it fails, the engine will be in doubt.

The internal working cavities of the pump are securely sealed. For prevention of malfunctions in the pump there is an oiler, through which it is convenient to inject lubricant. The sign of filling is a control hole through which excess lubricant comes out. As a lubricant, the usual "Litol" is used. In order to learn about the leakage in the pump casing, there is a special drain hole. If it flows from there, then the oil seals are no longer held and are subject to replacement.

Thermostats and branch pipes

The pipes of the cooling system (KAMAZ) should be under good supervision. In the case of an unsealed connection, it is possible to lose a large amount of coolant and to overheat the engine. Particular attention should be given to the connection points of the nozzles at the radiator, water pump and thermostats.

Thermostats of the cooling system are responsible for controlling the flow of antifreeze. When the temperature of the liquid rises to 80 ^° C, a redirection occurs to the radiator, that is, the circulation starts to follow the "large circle". At the same time, part of the flow continues to flow through the "small circle". And only at a temperature of 93 ^° C the "small circle" valve is completely closed, and all the coolant begins to flow through the engine cooler.

Cooling system maintenance

The cooling system (KAMAZ 740) practically does not differ from previous models. You should also know that for the 740 engine, the Euro 0, Euro 2, Euro 3 and Euro 4 attachments do not change the cooling system. So, what do you need to do to better service the system?

The very first action that must be done every day when the car is in operation is to check the integrity of the entire system (monitor the leak marks) and top up the antifreeze to the recommended level. The coolant itself in the summer can be ordinary water, and in winter time - quality antifreeze or antifreeze. For operation in severe regions of the north, a heating system is installed in the cooling system.

Other maintenance activities that are planned are:

• Checking the tension of the drive belt;
• Maintenance of the water pump (bearing lubrication plus checking and replacing oil seals);
• Checking the tension of the drive belt;
• Complete crimping of the cooling system;
• Checking the quality of the antifreeze and its possible replacement;
• Flushing the system in the event of a strong clogging.

Crimping

The cooling system (KAMAZ 65115) must have full tightness. Visual inspection is good, but it may not show places that are about to start missing. To identify such weaknesses, it is good to use a manometer and a pump to create pressure.

For crimping it is enough to apply pressure to the upper inlet of the radiator with a pump, start the engine and look after the gauge reading. If everything is good and there are no gaps in the system, the arrow of the device will not change its position. Otherwise, when the arrow begins to drop, it remains only to find the problem place.

Replacing the coolant

Cases when it is required to replace the whole cooling system liquid are not so rare. The simplest version is winter, and simple water is in the system. Also, replacement may be required in case of liquid loss of its cooling properties or heavy contamination.

The capacity of the cooling system (KAMAZ) is 25 liters. Of these, the water "shirt" is 18 liters. To replace the liquid, the drain of the old one is produced first. To do this, you need to open the bottom valve of the radiator, the drain cock at the heat exchanger and the pump in the heating system, as well as the pipes of the liquid supply in the cabin heating system. Do not forget to unscrew the expansion tank cap.

After the liquid has completely merged, all the valves are closed. And the entire volume of the cooling system (KAMAZ) is poured through the expansion tank. The new antifreeze is selected depending on the time of year and the operating conditions of the car. At the same time, it is not necessary to flaunt the import options in beautiful canisters. Domestic cooling fluids have exactly the same properties that meet international quality standards.

Flushing the cooling system

Washing the cooling system is possible in many ways. In case of minor contamination, rinse with plain water. To do this, the old coolant is drained, and water is poured in place of it. The engine starts and warms up at idle. After that, the water is drained, and the entire cycle is repeated several times until completely purified.

If the contamination in the system is significant, it is best to use special ready-flushed washes. In this case, there are quick options when washing is simply added to the old antifreeze, and then everything merges. But it is better to use washing solutions when the old cooling liquid is already drained. It should also be taken into account that cleaning solutions for the water "shirt" of the engine will differ. Radiator cooling system should be washed separately for more efficient cleaning. For this purpose, a 2.5% hydrochloric acid solution proved to be well established.

From the flushing characteristics, you should know that the direction of the flushing stream should be the opposite of the normal course of the coolant. It will be more effective to flush the system with water or a chemical solution under pressure.

Troubleshooting

The cooling system (KAMAZ 5320) should work without deviations from inspection to inspection. But cases are different and malfunctions can arise unexpectedly. Knowing the weaknesses of the system will help to quickly identify the problem and solve it on the spot.

Infringement of tightness of system is solved by a finding of a place of a leak and whenever possible its elimination. For this, a visual inspection is often enough. All connection points, a water pump, a radiator, a coupling are checked. Worn out nipples in this case it is better to simply replace. Radiator leakage can be eliminated by soldering or by muffling leaky tubes. The decision to replace the radiator is taken individually, because it is sufficiently repairable and well washed when removed.

Wear and lamination of the drive belt on detection is better to solve the replacement. If there is a suspicion of poor performance of the thermostats, it is convenient to check them by heating the lower radiator tank. At a temperature of 85 ^° C, that is, when the thermostat valve starts to open, the tank should warm up. If this does not occur, then the valve is defective and the thermostat should be replaced.

The cooling system (KAMAZ Euro 2) does not differ from its earlier versions and later too. The problems that may arise in the cooling system are the same in their features. One of these faults is the ingress of coolant into the lubrication system. It can be found by descending antifreeze without any leak marks. The cause may be worn cylinder head gaskets, as well as leaks through the cylinder liner seals. The problem is solved by replacing worn engine gaskets.

Conclusion

Care of the car must be regular and comprehensive. None of its systems can have privileges. At the same time, the knowledge of the weak points of a particular car helps a lot. KAMAZ, whose cooling system has no visible problems, should still be inspected regularly and have a full-scale maintenance.