A fan is wound on the water pump shaft in front. This fan is used to provide additional airflow through the heatsink. The fan contains a viscous coupling. As soon as the air coming from the radiator reaches a temperature of about 90°C, the bimetallic strip in the viscous coupling turns on the fan. The fan will then rotate at a speed equal to the engine speed and provide additional air to the radiator until the temperature of the passing air drops to about 60°C. The viscous coupling is then disengaged and the fan speed is reduced.
Due to the fact that the fan does not run constantly, the useful engine power is increased and fuel consumption is reduced.
Attention: When the engine is hot, before opening the radiator cap, cover it with a thick cloth to prevent burns from hot coolant or steam. The cover may only be opened when the coolant temperature is less than 90°.
Scheme of the circulation of the coolant of the engine of the M52 series
1 - radiator;
2 — expansion tank;
3 - heater radiator;
4 - thermostat;
5 - water pump;
6 - cylinder block;
7 - return of the coolant;
8 - coolant supply;
9 - throttle valve heating;
10 - valve (tap) heater.
Scheme of the circulation of the coolant of the M30 series engine
1 - radiator;
2 - input;
3 - exit;
4 - thermostat;
5 - water pump;
6 - channel block of cylinders / cylinder head;
7 - expansion tank;
8 - heater radiator;
9 - heating solenoid valve;
10 - additional water pump;
11 - exhaust pipeline.
A thermal accumulator can be installed as an additional equipment. Its task is to accumulate heat in the coolant and return it the next time a cold engine is started.
Thanks to this, the heating works faster and the engine warm-up time is reduced. The heat accumulator is an insulated vessel in the driver's footwell, which is filled with a chemically stable substance. The battery is connected in parallel with the coolant circuit and exchanges heat with the coolant. With the help of various solenoid valves, the flow of coolant is controlled in the process of accumulation and release of heat.
M70 series engine cooling circuit - features
The system is closed and has an expansion tank. The expansion tank is located at the rear in the middle of the engine compartment. Coolant is poured only through the cap of the expansion tank. Thanks to the sensor-switch for level control in the expansion tank, the coolant level is controlled.
The coolant pump on the front of the engine pumps coolant through the system.
The radiator on the front panel of the car gives off the generated heat to the environment. During normal vehicle operation, a headwind is sufficient for cooling.
When the car is stopped or driving slowly, the air supply is maintained by a temperature-controlled fan on the axis of the water pump and an additional fan in front of the radiator.
For interior heating, a separate pump draws coolant and passes it through the interior heater radiator.
Scheme of the circulation of the coolant of the M70 series engine
1 - radiator;
2 - stock;
3 - source;
4 - thermostat;
5 - water pump;
6 - channel of the right cylinder head;
7 - channel of the left cylinder head;
8 - connecting pipe to the drain;
9 - expansion tank;
10 - heater radiator;
11 - additional pump with valve.