Engine cooling system
All models of vehicles discussed in this manual are equipped with a positive pressure engine cooling system with thermostatically controlled circulation of the working fluid. The water pump is fixed on the engine block and provides pumping of the coolant through the cooling path of the latter. The flow of fluid washes the areas where each of the cylinders in the block is located, after which it is directed to the rear of the engine. Cast-in-the-block and cylinder-head cooling ducts provide intensive cooling for intake and exhaust ports, spark plug areas and exhaust valve guides.
From the moment the engine is started, the cooling system goes through three modes of operation: at the first stage, until the temperature of the coolant has risen above a certain value, it circulates in a small circle from the working circuit of which the radiator is excluded. As the liquid warms up further, the poppet valve of the wax-filled thermostat included in the system path opens and a radiator is connected to the circulation circuit. Further, when the temperature of the coolant reaches the next control value, a temperature-sensitive sensor-switch is activated, which activates the fan of the cooling system, which pumps additional air flow, which greatly increases the efficiency of the radiator heat exchanger.
The cooling system is hermetically sealed and sealed with a radiator/expansion tank cap capable of withstanding a certain amount of excess pressure, which increases the boiling point of the coolant and thus the efficiency of heat dissipation through the radiator. When the internal pressure in the system exceeds a certain value, an excess of coolant flows through the connecting (overflow) tube into the expansion tank. As the system cools down, the fluid automatically returns from the reservoir to the radiator.
Refueling of the coolant into the system is carried out through the neck of the expansion tank (see chapter Ongoing care and maintenance), which at the same time also acts as a receiver, accumulating the excess liquid displaced from the radiator.
In view of the above design features, such a cooling system is called closed, since it excludes any functional loss of the working fluid.
On some gasoline models, as well as on diesel models with an M612 engine, an electric preheater is built into the water circuit of the cooling system, which provides accelerated engine warm-up in cold weather. The heater can be powered by a 230 or 115 V power supply. The power consumption of the heating element is 500 W.
Note. The electric heater can be individually installed on the respective models as an optional extra.
Heating and ventilation system
The heating system consists of fans and heat exchangers located in the blocks of the front and rear parts of the cabin. The hot coolant flows through the heat exchangers. When moving the heater mode control handle located on the control panel (see Part Comfort devices), the valves open and hot air begins to flow into the passenger compartment. If you turn on the heater fan, air will be forced into the passenger compartment.
Outside air, before entering the cabin, is passed through a special filter, in which the main share of dust particles settles. The cabin air filter must be replaced on a regular basis in accordance with the Vehicle Maintenance Schedule (see chapter Ongoing care and maintenance). Violation of the filter patency leads to a decrease in the performance of the heating / ventilation / air conditioning systems.
The distribution of air flows of the ventilation system is carried out with the help of dampers. The possibility of switching of the modes of circulation of air is provided. The shutters are driven by servomotors.
Air conditioning system
See Section General information and security measures.
Specifications
Cooling system
Type of cooling system | Closed, with water pump, thermostat, radiator, fan (electric or viscous clutch) and separately installed expansion tank |
Coolant volume | See Specifications |
Coolant Composition (the proportion of antifreeze in the coolant to ensure frost resistance) | |
| 50% |
| 55% |
Working pressure in the system, atm | 1.4 |
Thermostat
Petrol models
Valve stroke, mm | at least 8 |
Valve activation temperature,°С | |
| 85 ÷ 89 |
| 102 |
Cover of a path of the cooling system
Response pressure of the safety valve built into the cover, atm | |
| |
| 1.4 + 1 |
| 1.4 – 1 |
| |
| 1.4 ± 1 |
| 2.0 ± 1 |
Depth of rarefaction leading to actuation of the vacuum valve, atm | 0.1 |
Cover testing pressure, atm | 1.4 (pressure must be maintained by the lid for at least 2 minutes) |
Air conditioning system
Refrigerant type | R134a |
Refrigerant volume, g | |
| 1050 |
| 1070 |
Compressor oil volume, cm3 | 120 |
Type of refrigerant oil | Synthetic PAG |
Amount of compressor oil to be added when replacing the condenser, see3 | 20 |
The amount of compressor oil to be added when replacing the dryer receiver, see3 | 10 |
The amount of compressor oil to be added when replacing the refrigeration line, see3 | 10 |
Amount of compressor oil to be topped up after sudden system emptying (destruction of the connecting tract), see3 | 40 |
Tightening force of threaded connections, Nm
Cooling system
M112/113
Collars of fastening of hoses of a cooling path | 3 |
Bolts of fastening of a casing of the thermostat (M6) | 10 |
Union nut for ATF cooling line on radiator | 20 |
Bolt for fastening the fan impeller to the viscous coupling | 10 |
Bolt for fastening the viscous coupling to the bearing housing (tightened with a special tool) | 45 |
Alternator fastening screws | 42 |
Bolts of fastening of a damper of a tensioner of a belt of a drive of auxiliary units | |
| 25 |
| 35 |
Self-tapping bolts for fastening the water pump to the timing cover | |
| |
| 14 |
| 10 |
| |
| 35 |
| 25 |
Bolt of fastening of a pulley of the water pump | 10 |
M612
Screws of fastening of the finishing panel of a cover of a head of cylinders | 10 |
Screws of fastening of the finishing panel of the air distributor | 10 |
Bolts of fastening of a casing of the thermostat | 9 |
Union nut for ATF cooling line on oil cooler | 25 |
Bolt for fastening the fan impeller to the viscous coupling | 10 |
Bolt for fastening the viscous coupling to the bearing housing (tightened with a special tool) | 45 |
Bolt of fastening of a pulley of the water pump | 35 |
Bolts for fastening the water pump to the timing cover | |
| 14 |
| 20 |
M628
Bolts of fastening of a casing of the thermostat | 9 |
Union nut for ATF cooling line on oil cooler | 25 |
Bolts of fastening of a bearing beam of a radiator to the bulkhead panel | 19 |
Bolt of fastening of a pulley of the water pump | 25 |
Bolts of fastening of the water pump to a crankcase of the engine | 10 |
Bolt of a collar of fastening of the circulation pump of an additional heater (STH) | 4 |
Heating/Ventilation/Air Conditioning Systems
Nut on the expansion valve | 10 |
Bolt of fastening of the expansion valve to the evaporator heat exchanger | 8 |
Attaching the pressure/temperature switch to the pressure line | 8 |
Compressor mounting bolts | |
| 23 |
| 20 |
Fastening refrigeration lines to the compressor | |
| 23 |
| 20 |
Union nut for fastening the refrigeration line to the condenser | 33 |
Fastening lines to the receiver-drier | 17 |