Engine cooling circuit

The engine cooling system is a water-cooled system with a circulation pump and a temperature controller (thermostat). The coolant has anti-corrosion properties and can be used throughout the year. Before the onset of the winter season, its frost resistance should be checked. The cooling system cover has a safety valve that can withstand pressure in the cooling system from 0.9 to 1.15 bar and thereby raise the boiling point of the liquid to about 120°C.

The water pump supplies coolant from the thermostat housing. From the pump, the coolant enters the engine crankcase and washes the cylinders there. It then flows into the cylinder head and cools the combustion chamber and valves. From the cylinder head there is a branch to the intake manifold heater, from where the fluid returns to the expansion tank. From the right cylinder head, coolant flows forward to a heat exchanger for heating. When the heater valve is open, fluid circulates through the heater circuit.

In a carburetor with sequential inclusion of chambers 2EZ (57 kW motor) the automatic engine start system has electric heating and coolant heating. At a coolant temperature of about 60°C, the electric heating of the automatic engine start system and allows the working mixture to be turned off by a temperature switch.

When the coolant temperature rises, the thermostat opens the damper on the large coolant circuit. Thanks to this process, the large circuit is switched on only when the temperature requires it.

The coolant level sensor is located in the expansion tank. This sensor works like a float switch. When the coolant level drops, the float drops and closes the contact. From this, the control lamp for reducing the coolant level on the dashboard starts flashing.

On cars with automatic transmission, a heat exchanger with a fan is installed under the rear seat, since the radiator cannot be installed for structural reasons. On all other passenger buses, the heat exchanger is installed as an option.