Mercedes S-Class W-140

1991-1999 of release

Repair and car operation



Mercedes S-Class
+ Mercedes-Benz Cars of a class S (W-140)
+ Operation manual
+ Routine maintenance
+ Engine
- Systems of cooling, heating
   Specifications
   + System of cooling of the engine
   - Systems of ventilation, heating and air conditioning
      Casing of the fan and ventilyatorny assembly - installation details (on an example of petrol model with the M120.980/982 series engine)
      Air central air - additional information and precautionary measures
      Arrangement of basic elements of automatic central air of air
+ Power supply system and release
+ engine Electric equipment
+ gear shifting Box
+ Avtomaticheckaya transmission
+ Coupling
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment



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Systems of ventilation, heating and air conditioning

See also Section Comfort of Head Operation manual

The air submitted by system of ventilation to salon of the car through the filter, can be warmed up or cooled depending on a choice of the driver and passengers. The heater or the conditioner settle down in salon, in the case under the dashboard. All stream of air submitted to salon goes for heating or cooling through the same casing. The temperature and speed of a stream of air is regulated by means of governing bodies located on the control panel.

Scheme of system of cooling

1 — the Broad tank
2 — the Cover
3 — the Built-in silikogelevy tank
4 — the Intaking branch pipe
5 — the Radiator
6 — the Thermostat
7 — the Ventilating tube
8 — the Stream from the engine to a radiator
9 — the Stream from a radiator to the engine
10 — the Pump of system of cooling

11 — the Oil radiator
12 — the Block of cylinders
13 — the Head of the block of cylinders
14 — the Forcing pipeline of a heater
15 — the Heater of stekloomyvatel
16 — a heater Radiator
17 — the Valve of a double pulsation
18 — the Circulating pump
19 — the Returnable tube of a heater

Heat allocated at operation of the engine, is transferred by cooling liquid to the radiator of a heater located in salon. The brought stream of air from system of ventilation passes through a radiator and heats up heat of cooling liquid of the engine proceeding in a radiator. Extent of heating is regulated by means of mixing in a certain ratio of cold and hot air by means of a mixing zaslonka with the servo-driver.

The used air is removed from salon through ventilating openings with return valves.

The increase in a consumption of air via the heat exchanger provides the fan of fresh air.

If it is necessary to disconnect supply of fresh air, for example, at a bad smell, the system is switched in a circulation mode at which in salon air available there circulates only.

System switching in a mode of circulation proves to be true activation of a control lamp (see. Head Operation manual).

Central air of air of salon

Functional schemes of typical central air of air

Working path of a forward contour of To/in system

And — the Entrance opening of cooling liquid
In — the Return stream of cooling liquid
1 — the Engine
2 — the Block of pumping of heating of salon

3 — the Heat exchanger of a heater of salon
6 — the Radiator of heating of a windscreen (screen wiper)
7 — Termoklapan, windscreen heating (screen wiper)
8 — Termoklapan, a liquid heater for windscreen washing


Working path of a back contour of To/in system

And — the Input of cooling liquid
In — the Return stream of cooling liquid
1 — the Engine
2 — the Block of pumping of heating of salon
3 — the Heat exchanger, a heating system

4 — the pumping Block, climate control of a back part of salon
5 — the heater Heat exchanger, climate control of a back part of salon
6 — the Radiator of heating of a windscreen (screen wiper)
7 — Termoklapan, windscreen heating (screen wiper)
8 — Termoklapan, a liquid heater for windscreen washing


Works with central air should be carried out by a specialized workshop. At all do not open a contour of circulation of a coolant as at contact with skin the coolant can cause frostbite.

By means of central air air temperature in salon can go down below external temperature.

At system work humidity in salon decreases. In the crude weather, arriving fresh air previously it is cooled, then again heats up to the set temperature. Thus its drainage is made. By means of this procedure the zapotevaniye of glasses is removed.

Central air consists of the compressor, the condenser, a throttle, the evaporator, capacity with a coolant and pipelines. In system the coolant (R134á type) which depending on temperature and pressure can be in a liquid or gaseous state circulates.

The conditioner compressor through a ridge belt is given in rotation from a cranked shaft of the engine. He creates pressure to the 30th bar in a contour of cooling of installation owing to what the coolant representing gas, heats up. In the condenser the coolant is cooled with air proceeding outside (cooling air remains in environment). Thereof the warmed-up coolant is condensed, turning into liquid. Having big pressure, it is passed through a throttle therefore its pressure falls. After that the coolant evaporates in a contour, at the same time strongly being cooled. In the evaporator the coolant selects heat from air blown through it. Thereof air is cooled. The cooled air arrives in car salon. As a result of heating in the evaporator the coolant turns into gas and under low pressure arrives in the compressor then process of circulation repeats.

Security measures at service of the air conditioner

Central air should be served by exclusively prepared technicians trained in safe working methods with use of the appropriate equipment with observance of rules of depressurization, acquainted with receptions of collecting and order of storage of an automobile coolant.
  • Do not allow contact of a coolant to skin;
  • At work near central air put on goggles;
  • At coolant hit on skin or eyes do not pound the struck place. Immediately wash out cold water within not less than 15 minutes. Immediately address to the doctor or in medical institution. Self-treatment is not allowed;
  • The coolant is stored in a new cylinder under pressure. Store a cylinder at temperature not above 50°С. Take the measures excluding falling of a cylinder from height or other situations which can lead to its damage;
  • Works should be carried out in well aired room. The coolant quickly evaporates, leads to reduction of access of oxygen and the complicated breath;
  • The gaseous coolant is heavier some air and rather quickly should gather below, for example, under the car;
  • At combustion of a coolant poisonous gas is formed. Store a coolant far from open sources of fire. Do not smoke. When using an ardent techeiskatel avoid smoke inhalation;
  • At carrying out welding works near central air to influence of high temperature or an open flame. The overheat can lead to pressure increase in system and to ignition;
  • Condenser or evaporator cleaning by means of water vapor is not allowed. It is necessary to use only cold water or the compressed air.