Mercedes C-Class

W203 since 2000 of release

Repair and car operation



Mercedes-Benz
+ Mercedes-Benz Cars of a class C (W-203)
+ Operation manual
+ Routine maintenance
+ Engine
- Cooling and heating systems
   + cooling System
   - Systems of ventilation, heating and air conditioning
      Removal and installation of ventilating deflectors
      Removal and installation of electromotors of a drive zaslonok
      Removal and control unit installation by a heater and conditioner
      Removal and installation of the electromotor of the fan of a heater or conditioner
      Removal and installation of an electronic regulator of the fan of a heater or conditioner
      Removal and installation of sensors of the conditioner
+ Power supply system and release
+ engine Electric equipment
+ Manual transmission
+ Automatic transmission
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment







Systems of ventilation, heating and air conditioning

General information and security measures

Distribution of air streams


Scheme of a contour of the conditioner of air

1 — the Fan
2 — the Evaporator
3 — the Broad valve
4 — the Tank
5 — the condenser Fan
6 — the Condenser
7 — the Compressor
and — External air for condenser cooling
b — the Warm air which is taken away outside
with — not cooled air going through the fan
d — the Cooled air going to salon
And — the High pressure, gaseous
In — the High pressure, liquid
With — Low pressure, liquid
D — Low pressure, gaseous

Additional electroheater. Diesel engine

1 — the electroheater Block
2 — Sealing laying
3 — the Heating element

Management of an air stream and filters of central air of air


The fresh air submitted by system of ventilation to salon of the car through filters of rough and thin cleaning, can be warmed up or cooled depending on a choice of the driver and passengers. The heater, on models without the conditioner, or the conditioner of air settles 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.

Regulation of speed of rotation of the fan is carried out by the electronic device, Heat allocated at operation of the engine, 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 external air in salon does not arrive.

System switching in a mode of circulation proves to be true fire of a control lamp.

If on the car the diesel engine is established, there is the additional electric heater which has been built in a contour of cooling of the engine, and included at low temperature of external air. If the external temperature falls below +8°С and at the same time the temperature of cooling liquid makes less 70°С, the additional heater joins, depending on the provision of a regulator of temperature in salon, and automatically lifts temperature of cooling liquid that provides heating of salon of the car.

The additional heater is located on the block of cylinders, at the left over a starter, looking in the direction forward.

Works with central air should be carried out by experts.

The conditioner of air is capable both to warm up and cool, and to drain air arriving in salon. In the crude weather, arriving fresh air previously it is cooled, then again heats up to the set temperature. Thus there is a condensation of excessive moisture of air, i.e. its drainage. Thus the zapotevaniye of glasses is eliminated.

The drainage mode, depending on humidity of air, has three steps of management.

The conditioner consists of a heater and the refrigerator. The conditioner refrigerator - from 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 compressor of the conditioner is given in rotation from a cranked shaft of the engine by means of a ridge belt. He creates pressure to 30 atm. in a contour of cooling of installation owing to what the coolant representing gas, heats up. In the condenser the coolant is cooled with external air (not arriving in salon). 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, at the same time strongly being cooled. In the evaporator the coolant selects heat from air blown through it. 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.

To order the car can be equipped with the automatic conditioner of air (climatic installation). Two options of the installations, differing touch management and comfort automatic equipment are thus possible.

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, has no smell. Its accumulation leads to reduction of access of oxygen and difficulty of 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.