Almost all car enthusiasts know that a car has an engine cooling system. UAZ Loaf or 452 is equipped with a simple design of the power unit, and therefore the rest of the systems have simple design features.

The purpose of the cooling system

The UAZ Bukhanka engine cooling system is designed to cool the engine during operation. So, the cooling elements remove the generated heat from the cylinder block and the head with the help of coolant and cool it in the radiator.

During operation, the power unit of the car heats up to exorbitant temperatures and if there is no cooling, then the engine parts will simply overheat and deform. Although, such situations also occur in the presence of a coolant system, in the case when it is not in working order or one of the important elements is out of order.

The operating temperature of the engine on the UAZ Loaf is 80-100 degrees Celsius. It is in this interval that the thermostat opens to a large cooling circle.

Since this car does not have an electric fan, but a forced cooling system, additional cooling of the radiator is constantly on.

The power unit can overheat if one of the cooling elements is out of order. First, there will be an easy stage in which the motor will simply boil. But, there can be serious consequences, such as deflection and deformation of the cylinder head. At this stage, the situation can be corrected by ordinary grinding of the block head surface.

In the middle stage, engine elements may deform. This includes the valve mechanism. Subsequently, the head of the block will need major repairs, and this will come out at a considerable penny to the owner of the vehicle.

The severe stage is when the piston group collapses from strong exposure to heat. But, and this is not the worst thing that can happen, because if the coolant gets into the cylinders of the car, the engine will overtake a water hammer, in which overhaul does not always save.

Coolant system diagram

The diagram of the UAZ engine cooling system is quite simple, it is of a closed type with forced circulation of the coolant. "Cooling" circulates in a circle from the radiator, passing the water pump and thermostat into the cooling jacket, and then returns.

Consider the cooling scheme of the power unit on UAZs, and in particular on the engine marked 452:

Cooling system element

The main elements of the cooling system of the UAZ Bukhanka 452 engine are well-known parts: a radiator, a fan, a water pump, a thermostat, pipes, a water jacket and a temperature sensor. Also, a heater is part of the design.

So, let us consider what the main elements of engine cooling are, their structure and operation, as well as repair and revision.

Radiator and fan

UAZ vehicles can be equipped with 3-row copper or aluminum radiators, which provide maximum liquid cooling. Since the operation of the elements is quite long, the cooling process of the power unit is not always the same as it should be.

In this case, this is due to clogging of the channels inside the element. Often, the usual cleaning does not help, and the increased wear makes cracks in the tubes, which the owners actively solder, not wanting to buy new parts. The main purpose of the radiator is to cool the liquid that circulates from the engine using the wind flow.

The fan of the cooling system on the Loaf is forced, fixed on the pulley and runs constantly while the crankshaft is spinning. Many car enthusiasts upgrade this system and install electric fans, which are often turned on by the driver himself according to the temperature readings on the dashboard.

Water pump

The pump at the UAZ mechanical drive. The main purpose of the element is to continuously circulate coolant through the system. So, the water pump provides the flow of liquid into the radiator for cooling and vice versa. A malfunction of this element can lead to loss of "cooling" and overheating of the engine.

Thermostat

The main structural element is a thermostat. It circulates fluid and serves as a switch between the small and large circle in the system. To warm up the vehicle, the element is kept closed. When it reaches 80 degrees Celsius, it starts to open, thereby circulating fluid through the radiator.

The main malfunction can be considered jamming of the element, which can lead to overheating of the motor, since, as practice shows, the thermostat wedges on a small circle, and accordingly there will be no additional cooling and fluid flow through the radiator.

Nozzles and water jacket

Nozzles are a means of moving fluid through the system from the engine and its elements to the radiator and back. Failure of these elements leads to the loss of "cooling", which, in turn, lowers the coolant level in the system, and this is a direct path to overheating.

Water jacket - design features of the head and cylinder block. It is through these holes that the coolant flows, which takes heat for cooling. With a long service life, especially in water, corrosion can form inside the walls, which will lead to leaks and fluid loss.

temperature sensor

The temperature sensor on the Loaf is not the same as most motorists are used to seeing. This is an old-style element that does not include an electric fan, since a forced system is installed here, but simply displays the temperature readings on the dashboard.

Output

As you can see, the diagram of the UAZ Bukhanka (452) engine cooling system is quite simple. It can be easily repaired and broken parts can be replaced without much difficulty. This unit consists of components - a radiator, fan, water pump, thermostat, pipes, water jacket and temperature sensor.

The coolant sensor is fundamentally different from modern ones, since it does not turn on the fan, but simply shows the temperature of the "cooling".

from the book by E.N. Orlova and E.R. Varchenko "UAZ cars" maintenance and repair

Cooling system.

Cooling system (fig. 25) liquid, closed, with forced circulation.
Figure: 25 Engine cooling system diagram
1 - heater radiator
2 - heater tap
3 - cylinder head
4 - holes of the water distribution pipe
5 - gasket
6 - water distribution pipe
7 - thermostat
8 - outlet branch pipe
9 - filler neck
10 - blinds
11 - plug
12 - minimum mark
13 - tank
14 - pump of the cooling system
15 - impeller
16 - pulley
17 - fan
18 - radiator
19 - radiator drain valve
20 - inlet pipe
21 - block of cylinders
22 - drain valve of the cylinder block

Low-freezing liquid antifreeze A-40 is used as a coolant. At an ambient temperature below minus 40 C, antifreeze A-65 is used. The use of water is allowed.

For normal engine operation, the coolant temperature must be maintained within 80 ... 90 C. This is achieved using an automatically operating thermostat and blinds controlled by the driver.

To control the temperature of the coolant, there is an electrical indicator in the instrument panel, the sensor of which is screwed into the cavity of the water pump bracket. In addition, overheating of the coolant is signaled by a control lamp with a red filter installed on the instrument panel and connected by an electric wire to a sensor screwed into the upper radiator tank. The control lamp lights up when the coolant reaches a temperature of 92 ... 98 С. When the control lamp comes on, open the radiator shutters.

Figure: 26 Engine cooling pump
1 - nut
2 - shaft
3 - pump body
4 - control hole of the grease outlet
5 - grease nipple
6 - spacer sleeve
7 - sealing washer
8 - rubber cuff
9 - spring
10 - impeller
11 - the impeller mounting bolt
12 - control hole for liquid outlet
13 - bearings
14 - fan shaft hub
15 - belt
16 - pulley
17 - ventilator
18 - bolt

On UAZ vehicles with the UMZ-417 engine, a liquid, closed cooling system is used, with forced circulation of the coolant by a centrifugal pump of the cooling system. On the UAZ-3151 car and some other models, depending on the configuration, a pre-start integrated into the cooling system can be installed. Low-freezing liquid is used as a coolant.

For normal operation of the UMZ-417 engine, the coolant temperature must be maintained within 70-90 degrees. This temperature is achieved using an automatically operating thermostat that regulates the amount of liquid passing through the radiator and louvers, which regulate the amount of air that cools the radiator.

Coolant temperature control in the UMZ-417 cooling system.

To control the temperature of the coolant, there is an electric one on the instrument panel, the sensor of which is screwed into the cavity of the water pump bracket. In addition, overheating of the coolant is signaled by a control lamp with a red filter installed on the instrument panel and connected by an electric wire to a sensor screwed into the upper radiator tank.

The control lamp lights up when the coolant reaches a temperature of 92-98 degrees. When the warning lamp comes on, open the radiator blinds. Overheating can be caused by:

- reduced liquid level in the radiator
- weak fan belt tension
- movement with closed blinds or a closed valve of the insulation cover

Maintenance of the UMZ-417 engine cooling system.

The coolant level in the expansion tank is checked on a cold engine, it should be 30-40 mm above the "Min" mark. When the level of low-freezing liquid decreases as a result of its boiling away, it is necessary to add clean water to the cooling system, since water evaporates first of all from the liquid, due to the fact that the boiling point of water is much lower than that of ethylene glycol. If the level of the liquid decreases as a result of leakage, it is necessary, after eliminating the cause of the leakage, to top up the low-freezing liquid.

The low-freezing fluid in the UMZ-417 engine cooling system is replaced every 2 years or after 60,000 kilometers. It is recommended to flush the cooling system with clean water before filling with fresh fluid. The liquid from the cooling system is drained through two taps. One is located on the lower radiator tank, the other on the cylinder block, or, if a pre-heater is installed on the UAZ, then on its boiler.

Maintenance of the water pump of the cooling system.

Centrifugal type, driven by a V-belt from the crankshaft pulley. The pump design uses a ball-roller bearing, which is made integral with the pump shaft. The bearing has special seals to ensure that the lubricant inherent in the manufacture is retained. The bearing does not require additional lubrication during operation. Leakage of coolant through the inspection hole indicates a defective gland seal.

A part of UAZ vehicles with UMZ-4178 and UMZ-4179 engines can be equipped with a water pump in the design of which ball bearings are used. In such pumps, the cavity is sealed with a rubber cuff, which is tightly pressed by a spring against the sealing washer and the pump shaft.

The bearings of such a water pump are lubricated after one regular maintenance with Litol-24 grease through a grease fitting until the grease comes out of the control hole. Any excess grease must be removed as it can get onto the fan belt.

It is checked by pressing it between the pulleys of the water pump and generator with a force of 39 N. The deflection of the belt should be within 8-14 mm. To adjust the tensioning belt, loosen the mounting bolts, move it in the required direction, fasten the bolts and check the belt tension again.

Checking the operation of the cooling system thermostat.

The thermostat of a locking type with a solid filling is located in the outlet pipe located on the bracket of the cooling system pump, and acts as a result of the movement of the stem in the thermostat cylinder. The thermostat valve begins to open at a coolant temperature of 69-72 degrees and fully opens at a temperature of 81-85 degrees. The thermostat, turning on or off the radiator, automatically maintains the required temperature of the coolant in the engine.

The operation of the UMZ-417 engine without a thermostat is unacceptable, since when it is removed, the main flow of coolant will circulate in a small circle of the cooling system, bypassing the radiator, which will lead to engine overheating.

The operation of the thermostat is checked simultaneously with flushing the cooling system, as well as in case of systematic overheating of the engine, with the correct operation of the power supply and ignition system. To check, the thermostat together with the thermometer is placed in a vessel with water heated to a temperature of 90-100 degrees. Then, with gradual cooling of the water, the start and end temperatures of the thermostat valve are controlled. The defective thermostat is replaced with a new one.

You can also check the serviceability of the thermostat by heating the inlet pipe of the upper radiator tank when the engine warms up. With a faulty thermostat, this pipe heats up immediately after starting the engine, with a good one - after the water temperature in the engine block reaches 60-70 degrees according to the water temperature indicator on the instrument panel.

Cooling system radiator cap.

Seals the radiator hermetically and communicates the cooling system with the expansion tank only through the outlet and inlet valves. The outlet valve opens when the pressure in the cooling system rises to 44.1-58.8 kPa and releases coolant or vapors into the expansion tank. The intake valve opens at a system vacuum of 0.98-9.8 kPa and lets coolant from the expansion tank into the radiator.

The radiator plug sealing gasket prevents vapors or coolant from escaping through the gap between the radiator neck and the radiator plug locking spring. For normal operation of the radiator plug, it is necessary that the valve gaskets and the gasket between the radiator neck and the locking spring are in good order.

Fan and cooling fan drive clutch.

Four-blade, modular, attached to the water pump hub. The fan is driven together with the water pump by a V-belt from the crankshaft. Some UAZ vehicles can be equipped with a viscous fan drive clutch designed to reduce fuel consumption, reduce fan noise, facilitate warm-up of a cold engine and maintain the thermal regime of the engine within optimal limits.

In the gap between the driving and driven parts of the clutch there is a high-viscosity working fluid, through which rotation is transmitted from the clutch shaft mounted on the hub of the cooling system pump pulley to the clutch housing and the fan attached to it. The clutch is switched on and off automatically depending on the air temperature behind the radiator. The coupling is not collapsible.

If the bypass hole is clogged, the clutch stops engaging or does not fully engage, and the engine may overheat. To eliminate the indicated malfunction, unscrew the coupling from the hub, remove the fan and unscrew two pins from the coupling housing. Then it is necessary to drain the working fluid through the holes for the studs and thoroughly rinse the inner cavity of the coupling with gasoline.

Allow gasoline to drain completely and pour 40 grams of PMS-10000 polymethylsiloxane fluid into the coupling through one of the holes. The second hole must be kept open for air to escape. After that, screw the studs into the housing, fix the fan and install the coupling on the hub of the cooling system pump pulley. Please note that the connection of the coupling shaft to the hub has a left-hand thread. The outer surface of the coupling should be kept clean.

Cooling system shutters.

Installed in front of the radiator. The shutters are controlled from the driver's seat using a pull rod. When pulling the traction handle towards itself, the blinds close, when sliding in, they open.

Inspection and maintenance of the cooling system shutters.

The blinds are checked for completeness of opening with the drive handle fully pushed in. If the shutters do not open completely, then the following operations must be performed:

- loosen the screw securing the drive rod in the hinge of the lever located on the louvers
- fully open the shutters by turning the drive lever counterclockwise
- push the blinds drive handle to the full and fix the drive rod in this position in the lever pivot coupling
- check if the shutters of the blinds open and close completely by pushing or pulling the drive handle

If the drive handle moves with great effort, then it is necessary to lubricate the axes of the shutters and the rod. The traction is lubricated by first removing it from the shell and cleaning it. In the cold season, in addition to the blinds, it is recommended to install an insulating cover with a hinged valve.

Replacing the coolant in the UMZ-417 cooling system.

When draining the liquid, the radiator plug is removed, the heater filler plug is unscrewed and the heater tap is opened. The remaining liquid in the expansion tank and the hose connecting it to the radiator is removed through the disconnected hose from the radiator or by lifting the reservoir above the radiator.

In the absence of a low-freezing liquid, it is allowed to use clean water, if possible, not hard, in order to avoid intense scale deposits, which will lead to engine overheating and increased fuel consumption. In this case, when the ambient temperature is below 0 degrees, the hose connecting the radiator with the expansion tank must be disconnected from the expansion tank and directed downward to remove steam from the radiator. The presence of water in the expansion tank at negative temperatures is not allowed.

Flushing the cooling system of the UMZ-417 engine.

As water is used as a coolant, the efficiency of the cooling system is noticeably reduced as a result of scale deposits on its internal surfaces and, as a result of deterioration of water circulation in the system. In this case, the cooling system must be flushed. The engine and radiator are flushed separately so that rust, scale and sludge from the engine cooling jacket does not clog the radiator. Remove the thermostat before flushing the engine.

The direction of the jet during flushing should be opposite to the direction of movement of the water during normal operation of the cooling system. Do not use alkaline solutions to flush the engine block cooling jacket, as they cause corrosion of the engine head and cylinder block.

The cooling system of the UMZ-421 engine is liquid, closed, with forced circulation of liquid and an expansion tank, with fluid supply to the cylinder block. For normal engine operation, the coolant temperature must be maintained within plus 80-90 degrees. Short engine operation at a coolant temperature of 105 degrees is permissible.

This mode can occur in the hot season when the car is moving with full load on long climbs or in urban driving conditions with frequent accelerations and stops. Maintaining normal coolant temperature is carried out using a two-valve thermostat.

The cooling system of the UMZ-421 engine includes a water pump, a thermostat, water jackets in the cylinder block and head, a radiator, an expansion tank, a fan, connecting pipes, and a body heating radiator.

Cooling system water pump UMZ-421.

The cooling system pump of the UMZ-421 engine is of a centrifugal type, driven by a V-belt from the crankshaft pulley. Belt dimensions 10.7x8 mm, belt length on UAZ cars - 1030 mm, on GAZelle cars - 1018 mm. The pump body and cover are made of aluminum alloy. The pump design uses a special double-row ball bearing 5НР17124Е.Р6Q6 / L19 or 6-5НР17124ЕС30, with a double-sided seal, with a roller instead of the inner rings.

Since 1999, an armlen impeller of the PP SV-30 brand with straight radial blades, designation 421.1307032-04, has been used on water pumps, instead of the previously used impeller with backward curved blades, designation 4022.1307032. As a result of the transition to a new impeller, the performance and supply pressure of the water pump were significantly increased, which made it possible to ensure reliable operation of the engine cooling system, as well as to increase the efficiency of the interior heating system.

Thermostat type TC-107.

A two-valve, with a solid filler, is located in the outlet pipe of the cylinder head and is connected by hoses to the water pump and radiator. The main valve of the thermostat begins to open at a coolant temperature of 78-82 degrees, fully open at a temperature of 94 degrees.

When the main valve is closed, the liquid in the engine cooling system circulates, bypassing the radiator, through the open additional thermostat valve inside the engine cooling jacket. When the main valve is fully open, the auxiliary valve is closed, all the liquid passes through the cooling radiator.

The thermostat automatically maintains the required coolant temperature in the engine, shutting off the circulation of fluid through the radiator. In cold weather, especially at low engine loads, almost all of the heat is removed as a result of the cold air blowing over the engine, and the coolant does not circulate through the radiator.

The thermostat must not be removed from the cooling system, since in the cold season, the engine without a thermostat takes a long time to warm up and runs at a low coolant temperature. As a result, its wear is accelerated, fuel consumption increases, there is an abundant deposition of resinous substances in the engine, and the normal air temperature in the car interior is not ensured.

In the warm season, in the absence of a thermostat, most of the coolant will circulate in a small circle through the engine cooling jacket, bypassing the radiator. This will result in overheating of the engine.

Expansion tank of the cooling system.

On UAZ cars, the expansion tank of the UMZ-421 engine cooling system is directly connected to the atmosphere. The regulation of the exchange of fluid between the tank and the closed volume of the system is regulated by two valves: inlet and outlet, located in the radiator plug. The outlet valve opens at an overpressure of 0.45-0.60 kgf / cm2, and the inlet valve opens at a vacuum of 0.01-0.1 kgf / cm2.

Circulation of coolant in a small circle.

When the engine warms up, when the coolant temperature is below 80 degrees, a small circle of coolant circulation operates. The upper thermostat valve is closed, the lower valve is open.

The coolant is pumped into the cooling jacket of the cylinder block by a water pump, from where, through the holes in the upper plate of the block and the lower plane of the cylinder head, the liquid enters the cooling jacket of the head, then into the thermostat housing and through the lower thermostat valve and the branch pipe to the inlet of the water pump. The radiator is disconnected from the main flow of the coolant.

For a more efficient operation of the interior heating system when circulating liquid in a small circle, this situation can be maintained for a long time at low negative ambient temperatures; there is a throttle hole with a diameter of 9 mm in the liquid outlet channel through the lower thermostat valve. This throttling leads to an increase in the pressure drop at the inlet and outlet of the heating radiator and more intensive circulation of fluid through this radiator.

In addition, throttling of the valve at the liquid outlet through the lower thermostat valve reduces the likelihood of emergency engine overheating in the absence of a thermostat, since the shunting effect of a small circle of liquid circulation is significantly weakened, therefore, a significant part of the liquid will go through the cooling radiator.

In addition, to maintain a normal operating temperature of the coolant in the cold season, UAZ cars have louvers in front of the radiator, with which you can adjust the amount of air passing through the radiator.

Circulation of coolant in a large circle.

When the temperature of the liquid rises to 80 degrees or more, the upper thermostat valve opens, and the lower valve closes. The coolant circulates in a large circle. The cooling system must be completely filled with liquid for proper operation.

When the engine warms up, the volume of liquid increases, its excess is pushed out due to the increase in pressure from the closed circulation volume into the expansion tank. When the temperature of the liquid drops, for example, after the engine stops working, the liquid from the expansion tank is returned to the closed volume under the action of the resulting vacuum.

UAZ "Bukhanka" is an all-wheel drive off-road vehicle. This model has been produced since 1957. This machine is used not only for its intended purpose, after all, it is a special technique, but it is also used by lovers of fishing and hunting.

The main advantage of this car is its versatility and huge cross-country ability. The salon can accommodate 10 passengers, and if necessary, it can be transformed as desired. The heart of the car is the ZMZ-402 and ZMZ-409 engines. Since the car is special, many are interested in how the cooling system of the UAZ "Loaf" is arranged.

General device

Closed-type liquid cooling is used in these cargo-passenger cars of the wagon layout. The coolant circulates in the system forcibly under the influence of a centrifugal pump. The manufacturer recommends using the domestic "Tosol" as coolants. However, in case of emergency, you can fill the cooling system of the UAZ "Loafs" and ordinary water. The volume, including not only the circuits of the cooling system, but also the heater, on most models ranges from 13.2 to 15.3 liters.

Cooling system diagram for ZMZ-402

It's pretty simple. This power unit is cooled by fluid that flows through two circuits.

The system is built according to a ring scheme and consists of several main components. The liquid moves from the radiator through the pipes to the thermostat, then passes through the engine cooling jacket. Then, by means of a water pump, it enters the radiator again. In addition, the cooling system of the UAZ "Loaf" with a 402 engine includes an electric fan, a temperature sensor, and heaters. Let's consider each element separately.

Thermostat

It is the most delicate component in the system. It most often fails - modern spare parts are not very high quality. The thermostat function is to control the coolant flow through the engine. The ZMZ-402 unit, like many others, has two coolant circulation circles - large and, accordingly, small.

When the driver starts the engine and it warms up a little, the liquid in the cooling system of the UAZ “Loaf” circulates only in a small circle. This allows the engine to warm up faster. When the temperature reaches about 70 degrees, the thermostat will work, and the coolant will flow through the cooling radiator in a large circle. Operating temperatures for the 402 engine are between 82 and 90 degrees. If the engine does not warm up to these temperatures, then this indicates that the thermostat is faulty. Often, due to wear, it will jam and will not open.

water pump

This is a very important element. Due to it, the liquid can circulate directly throughout the entire system. In this engine, the antifreeze circulates constantly forcibly. The pump consists of several elements - if necessary, it can be easily disassembled. The pump is located in the front of the cylinder block, and it is driven by a belt drive.

Radiator and cooling fan

When the liquid in the cooling system of the UAZ "Loaf" passes through the engine, it will warm up. It must cool down to cool. For this, a radiator is used. On these cars, the manufacturer installs mainly copper 3-row radiators. However, the owners prefer to install aluminum solutions instead. As the reviews note, with them the engine is cooled much more efficiently.

The radiator in the system acts as a cooler. It is cooled by the oncoming air flow while driving. When the car is stationary or moving at low speed, the air flow is weak and cannot sufficiently blow off the radiator. Then the fan comes in. In this car, it is a forced type. The element rotates when the engine is running, regardless of the coolant temperature. Thus, it is very difficult to overheat the engine.

Cooling jacket and pipes

To connect various units of the cooling system of the 402nd engine of the UAZ "Loaf", branch pipes are used. These are rubber products in the form of tubes. The elements are reliable enough, but if they are used for a long time, then they wear out - they age. Then the coolant can leak and its level drops. As a result, the motor overheats.

The cooling jacket is a necessary part, without which the motor simply will not cool down. The shirt runs through the entire cylinder block. It acts as a heat sink. The coolant is then led out to the radiator.

ZMZ-409 engine

This motor is distinguished by a different valve cover, an improved timing mechanism, and a different cylinder head gasket. The volume of the power unit also increased, which immediately led to the modernization of the cooling system ZMZ-409 UAZ "Bukhanki".

The design of the cooling system is typical for an internal combustion engine of this design, which was ever manufactured at the Zavolzhsky plant. The engine is equipped with a liquid closed forced system. There is also a radiator, a jacket in the cylinder block and in the cylinder head, a pump, an expansion tank, temperature sensors, an electric fan, a heater radiator and other elements. Note that the principle of operation of the cooling system 409 UAZ "Loaf" is simple and similar to injection motors. Here, the coolant also moves in a large circle and in a small one.

Radiator and fan

With these elements, the engine does not overheat above its operating temperature. On the first models with such a power unit, there was a three-row copper radiator, but after not very successful tests, they began to install aluminum ones. As for the fan, here it is already electric. The element is controlled by the ECU and the temperature data is read directly from the cooling jacket.

Thermostat

The function of this element is the same here. It is needed to open or close the path of the liquid from a small to a large circle, or vice versa.

This thermostat on the motor opens at a temperature of 75 degrees. This is one of the important parts of the engine. If the thermostat is faulty, the engine will overheat.

water pump

It forces the coolant to circulate throughout the system. This is an ordinary unremarkable water pump. Sometimes bearings jam in it, and then antifreeze leaks occur.

Heater

It is also one of the integral parts of the cooling system of the UAZ “Bukhanka” with the 409th engine. The heater consists of inlet and outlet pipes, as well as a radiator and an electric fan. The stove is actively used in winter, which has an even better effect on engine cooling.

Expansion tank

Gases and vapors generated in the system during its operation are squeezed into this container. It is also the coolant level. The tank plug is designed in such a way that excess air is forced out through it.

Temperature sensor

This element measures the temperature and gives the measurement results to the ECU. Further, the control unit regulates the temperature regime. You can find this sensor on the thermostat.

Disadvantages of the system

There is only one plus in the standard system - it works. The owners cannot say that it is flawlessly reliable. It's all about the quality of spare parts. But all the other advantages that this system has can be safely attributed to cons. On the 402 motor, the fan is too slow - the number of its revolutions is strictly limited by the pump. To have enough of them, you need a large radiator. In winter, you have to close this radiator so that the motor does not freeze. There are also problems with the operation of the heater. Without additional artificial pumping of antifreeze, you can not wait for heat.

All these problems can be solved by upgrading the cooling system 402 of the UAZ "Loaf" engine (replacing the radiator with a multi-section one, installing a second stove, and so on). Many owners are improving it to increase work efficiency.

So, we have found out how the cooling system of the UAZ "Loaf" with the 409th and 402nd model engines is arranged. The device is very simple, but the reliability of the system leaves much to be desired, as the owners say.