The engine cooling system is liquid, closed, with forced circulation of coolant

A bypass pipe (bypass) has been introduced into the cooling system, connecting the lower outlet pipe of the water jacket with the suction cavity of the water pump bearing housing.

Scheme of the cooling system is shown in fig. 1.

ZIL-131 engine cooling scheme

The temperature of the coolant must be within 80-95 ° C. An expansion tank can be installed on the vehicle upon special request (Fig. 2).

Radiator with expansion tank ZIL-131

During operation, make sure that the cooling system is always completely filled; the water level should not reach the upper edge of the filler neck by 40-50 mm.

When using a liquid that freezes at low temperatures (antifreeze), its level should not reach the upper edge of the filler neck by 80-90 mm.

If there is an expansion tank, the radiator must be filled completely, and the tank - up to half.

The radiator must be filled with clean and preferably soft water. Do not pour cold fluid into a hot engine.

In severe frosts, it is necessary to insulate the radiator, using insulating covers for the radiator lining and on the engine hood, and carefully monitor the coolant temperature gauge.

The operation of a cold engine leads to intensive wear of the piston rings and cylinders.

In order to increase the reliability of the cooling system and to protect it from freezing during severe frosts, it is recommended to use a special liquid that freezes at low temperatures (antifreeze).

Coolant is poisonous and should be handled with care. If even a small amount of this liquid enters the body, it can cause severe poisoning.

When pouring coolant, make sure that no air lock forms in the cooling system that prevents filling systems.

To avoid this, open the radiator drain cock. Close the tap only after the appearance of liquid from it.

The coolant from the cooling system must be drained through three taps: a radiator tap and two starting heater taps.

If there is an expansion tank, a fourth tap is added, installed on its bottom.

It must be remembered that when draining fluid from the cooling system, all taps must be opened, as well as the cap of the radiator or expansion tank.

In winter, after draining the water from the system, it is necessary to close the cock of the cab heater and open it again only after starting and warming up the engine.

The cranes are equipped with a remote control (Fig. 3), which ensures easy access to them when the engine hood is open.

ZIL-131 drain valves remote control

The control levers are located in the engine compartment above the engine. The heater boiler tap and the expansion tank tap do not have a remote control. Screw taps with ball seal.

If it is necessary to drain the liquid from the cooling system, the valve drive handle is unscrewed a few turns.

If it is necessary to drain the coolant into any dishes, rubber hoses must be put on the drain taps, the ends of which should be passed through special holes in the under-engine mudguards.

After completely draining the liquid before parking the car, leave the taps open.

If the taps freeze in the open position, they must be closed after filling the liquid when the engine is warming up, after the liquid flows from the taps.

When starting a cold engine in winter, it is necessary to carefully monitor the thermal regime of the engine.

If the engine is cold, the thermostat valve will prevent coolant from entering the radiator until it has warmed up in the cylinder jacket; during this period there is a danger of freezing of the liquid in the radiator

However, during severe frosts, the thermostat must not be removed from the engine cooling system.

The condition of the radiator cap valves should be checked periodically.

It is necessary to systematically monitor the condition of all seals, to prevent leakage of liquid from the cooling system.

It is strictly forbidden to start and short-term operation of the engine without coolant in the system cooling, as well as warming up the engine after draining the coolant to remove the remaining coolant from the system, as this can lead to destruction of the sealing rubber rings of the cylinder liners, falling out of the valve seats, burning the head gasket and warping of the aluminum head.

In cases where the cooling system is dirty, it must be flushed.

In the summer, it is necessary to systematically monitor the condition of the air channels of the core of the radiator of the cooling system and be sure to clean them if they are heavily clogged.

Cleaning can be done with a jet of compressed air directed into the air channels of the radiator core from the side of the fan shroud.