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 Pouring coolant into the engine through the radiator.

When filling the system, the coolant enters through the radiator neck, from where it gradually spreads through the cooling channels in the block and cylinder head. This allows air to be purged and prepares the circuit for circulation.

The main circulation element is the water pump. Its impeller, driven by the crankshaft or timing belt, creates pressure, ensuring a constant flow of coolant throughout the system.

Through the channel in the front crankcase cover, the coolant is redirected to the necessary cavities of the block. The design of these channels is calculated to distribute the flow evenly and avoid stagnant zones.

Cylinder cooling jacket.
These are cavities around the cylinder liners, where the coolant absorbs the main heat generated during fuel combustion. Thanks to the jacket, local overheating of the cylinder walls is prevented.

The cylinder head gasket has combined openings for coolant and oil. Through them, antifreeze passes into the head, maintaining the sealing of the combustion chambers and preventing mixing of the circuits.

The coolant enters the head and washes the areas around the intake and exhaust valves. This is where the thermal load is the highest, and heat removal is critically important.

Coolant outlet for heating the intake manifold.

This line connects two key units: the pump, which creates the flow, and the thermostat, which regulates the coolant route between the small and large circuits.

Heated antifreeze from the head flows into the thermostat housing, where it is decided whether it will go further to the radiator or back to the pump.

Thermostat shut-off element.
This is a thermosensitive valve, containing wax or another material that expands when heated. It controls the opening and closing of the path to the radiator.

Upper radiator hose. It directs coolant from the thermostat to the radiator.
Through this hose, hot coolant enters the upper part of the radiator and begins to move downward through thin tubes, releasing heat.

Radiator cap.
It has a valve mechanism that controls pressure. The cap prevents premature boiling of the coolant by creating excess pressure in the system.

Consists of two valves: inlet and outlet.
The outlet valve releases excess pressure into the expansion tank, while the inlet valve, when the engine cools, allows coolant back into the system, compensating for vacuum.

The circulation pump delivers coolant into the cylinder block jacket.
This creates a continuous cycle: coolant absorbs heat from the cylinders, then passes through the system and returns again.

When the coolant temperature is below 80 °C, the thermostat shut-off element blocks the path to the radiator.
This is the small circuit mode, when the radiator is not engaged, and the engine warms up faster to operating temperature.

Coolant from the head passes through the thermostat housing and returns to the pump, repeating the path.
Here the circulation is closed within the engine, minimizing heat loss.

Heat from the cylinders is transferred to the coolant.
During combustion, fuel releases a huge amount of energy, and without heat removal, the parts would overheat within minutes.

When the coolant heats above 80 °C, the thermostat shut-off element opens.
The thermostat gradually opens the passage to the radiator, regulating the flow so that the temperature remains within the optimal range.

In this case, the channels from the intake manifold and to the pump are blocked.
This directs the flow specifically into the radiator, eliminating the short path through the small circuit.

Coolant is directed to the radiator.
There it meets a powerful cooling airflow, which is enhanced by the fan.

In critical overheating, when the coolant expands significantly and creates high pressure, the outlet valve is activated.
This prevents system damage: the excess volume is released into the expansion tank.

The tank serves as a buffer, which accepts the excess coolant and stores it until the engine cools down.

When the engine cools and the coolant decreases in volume, a vacuum is created in the cooling system.
This is a natural process — the volume of liquid shrinks, and the internal pressure drops.

At the same time, atmospheric pressure presses on the coolant in the expansion tank.
Under external pressure, the antifreeze is forced back into the system.

When the vacuum reaches a certain value, the inlet valve opens.
At this moment, the coolant returns to the radiator, replenishing the level.

The previously expelled coolant returns to the system.
Thus, the system remains sealed and always full.