Audi A4, S4

since 2000 of release

Repair and car operation

Audi A4, S4
+ Introduction
+ Governing bodies and receptions of safe operation
+ Current leaving and service
+ Engine
- Systems of cooling, heating and air conditioner
   - Cooling system
      General information
      Antifreeze - means of protection from freezing
      Replacement of cooling liquid
      Removal and thermostat installation
      Thermostat check
      Replacement of hoses of system of cooling
      Removal and radiator installation
      Removal and installation of the fan of a radiator
      Removal and installation of the pump of cooling liquid
   + Systems of ventilation, heating and air conditioning
+ Power supply systems, release and decrease in toxicity of the fulfilled gases
+ Systems of electric equipment of the engine
+ Manual box of gear shifting
+ Automatic transmission
+ Coupling, power shafts and differential
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment


Cooling system

General information

Scheme of connections of hoses of system of cooling

1 — a heater Radiator
2 — the OZh Pipeline bottom
3 — the Broad tank
4 — Maslookhladitel
5 — the Inlet pipeline
6 — Nizhny a radiator hose
7 — the Top hose of a radiator

8 — the Radiator
9 — the OZh Pipeline top
10 — the Water pump with the thermostat
11 — Turbokompressor
12 — the Block and a head of cylinders
13 — the Target union

On some models the system of regulation of temperature of the cooling liquid, working according to the characteristic put in the control unit is applied. In comparison with usual system of cooling such system increases thermodynamic efficiency of the engine and thus optimizes the torque characteristic.

The system of the cooling working on the set characteristic, consists of the distributor of cooling liquid with the thermostat, an electric heating element, and also springs, for mechanical locking of channels of cooling liquid.

By means of the warmed-up thermostat the temperature of cooling liquid is regulated by the control unit the engine according to the characteristic put in it. The temperature, optimum from the point of view of given engine capacity is thus supported.

For example, at full loading of the engine the extending element heats up and thus the thermostat opens more. The temperature of cooling liquid that leads to more intensive cooling of chambers of combustion thereby decreases. Colder chambers of combustion lead to earlier ignition and by that to increase in a torque of the engine.

Cooling liquid goes through a radiator constantly working pump. Liquid passes through a radiator from top to down and is cooled with air passing through it. The fan of cooling liquid with the electric drive is applied.

Heater and ventilation

The heater consists of fans and the heat exchangers located in blocks of forward and back parts of salon. Hot cooling liquid passes through heat exchangers. When moving the handle of management by modes of the heater, located on the control panel, valves open, and hot air starts to arrive in car salon. If to turn on the heater fan, air will move in salon compulsorily.

Intaking air before getting to salon, passes through the filter (address to Head the Current leaving and service). The main share of particles of a dust will settle in the filter. It is necessary to observe periodicity of replacement of the filter. The filter littered by a dust will limit supply of air in salon that will lead to an air stagnation in salon.

Distribution of streams of air of system of ventilation is carried out with the help a zaslonok. The air circulation mode is provided. Zaslonki cope servo-drivers.