How is the cooling system of the UAZ "Loaf"?

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42

UAZ "Loaf" is an all-wheel drive off-road vehicle. This model has been produced at the Ulyanovsk Automobile Plant since 1957. This machine is operated 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 plus of this car is its versatility and great cross-country ability. The salon accommodates 10 passengers, and if necessary, it can be transformed in any way. 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 works.

Shared device

These passenger-and-freight wagon-mounted cars use closed-type liquid cooling. The coolant in the system circulates forcibly under the influence of a centrifugal pump. The manufacturer recommends using domestic Tosol as coolants. However, in emergency cases, you can fill in the cooling system of the UAZ "Loaf" and the usualwater. The volume, including not only the circuits of the cooling system, but also the heater, on most models is from 13.2 to 15.3 liters.

Scheme of the cooling system for ZMZ-402

It's quite simple. This power unit is cooled by a liquid that passes through two circuits.

The system is built according to the 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 the 402nd engine includes an electric fan, a temperature sensor, and heaters. Consider each element separately.

Thermostat

This is the most delicate component in the system. It most often fails - modern spare parts are not of very high quality. The function of the thermostat is to control the flow of coolant 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 402 engines are indicators ranging from 82 to 90 degrees. If athe motor does not warm up to these temperatures, then this indicates that the thermostat is faulty. Often, due to wear and tear, it jams and does not open.

Pump

This is a very important element. Due to it, the liquid can circulate directly throughout the system. In this engine, antifreeze circulates constantly forcibly. The pump consists of several elements - if necessary, it can be easily disassembled. The pump is located in 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 be cold to cool down. 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 noted by the reviews, with them the engine is cooled much more efficiently.

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

Cooling jacket and fittings

To connect variousnodes of the cooling system of the 402nd engine of the UAZ "Loaf" use pipes. These are rubber products in the form of tubes. The elements are quite reliable, but if they are used long enough, 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 passes through the entire cylinder block. It acts as a heat sink. Then the coolant is led to the radiator.

Engine ZMZ-409

This engine features 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 "Loaves".

The cooling system device is typical for internal combustion engines of this design, which have ever been 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 of the 409 UAZ Loaf is simple and similar to injection engines. 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. At firstmodels with such a power unit had 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 computer and coolant temperature sensors. Temperature data is read directly from the cooling jacket.

Thermostat

The function of this element is the same here. It is necessary to open or block the fluid path from a small to a large circle or vice versa.

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

Pump

It forces the coolant to circulate through all circuits of the system. This is an ordinary unremarkable water pump. Sometimes bearings jam in it, and then antifreeze leaks happen.

Heater

This is also one of the integral parts of the cooling system of the UAZ “Loaf” with the 409th engine. The heater consists of branch pipes - inlet and outlet, 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 formed in the system during its operation are squeezed into this container. It is also the coolant level. The tank cap is designed in such a way that excess air is forced out through it.

Temperaturesensor

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

System flaws

There is only one plus in the regular system - it works. Owners cannot say that it is impeccably reliable. It's all about spare parts. But all the other advantages that this system has can be safely written off as cons. On the 402nd motor, the fan is too slow - the number of revolutions is strictly limited by the pump. To get enough of them, you need a large radiator. In winter, this radiator has to be closed so that the engine does not freeze. There are also problems with the operation of the heater. Without additional artificial pumping of antifreeze, heat can not be expected.

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 modifying it, increasing the efficiency of work.

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