Audi A4

since 1994 of release

Repair and car operation

A4 Audi
+ Running gear
+ Regular servicing
+ Engines
+ Turbo-supercharging
+ exhaust System
+ cooling System
+ Fuel tank and fuel pump
- Air filter and absorption channels
   Dismantle of the loose leaf of the air filter
   Purge of the loose leaf of the air filter
   Replacement of the loose leaf of the air filter
   Preliminary heating of soaked-up air
   Being switched inlet collector
+ injection System
+ Coupling
+ Transmission and main transfer
+ Suspension bracket of wheels and steering
+ Brakes
+ Wheels and tires
+ Electrotechnical equipment
+ ignition System
+ Lighting
+ Alarm equipment
+ Tools and devices
+ Heating and ventilation
+ body Details
+ Salon
Search of malfunctions
Technical characteristics

Preliminary heating of soaked-up air

Six-cylinder engine

The device of automatic preliminary heating of soaked-up air is from the entrance party of the case of the air filter. Before it there is a problem of a podderzhivaniye of the favorable air temperature which is soaked up by the engine.

For this purpose there is the following reason: at cold weather the fuel and air mix is sated more if soaked-up air moves previously the heated up. The same amount of warm air occupies bigger volume, than cold air. As the engine can soak up only certain amount of air, at the included preliminary heating a little less air arrives – the mix becomes richer, fuel consumption raises. For continuous work of the engine it is necessary only at low temperatures.


Zaslonka of preliminary heating of soaked-up air is regulated by the thermostat which completely opens supply of warm air at temperature of-20 °C. At temperature increase the zaslonka is slowly closed until at temperature of +5 °C will not be closed completely.

Violations in work

If preliminary heating of air functions unsatisfactorily, it can lead to operational violations.

In a cold season:

  • Unstable idling after start of the cold engine at a warming up stage.
  • Bad switching, the engine it is inclined to interruptions.

In a warm season:

  • The lowered capacity, is not reached the maximum speed.
  • The increased fuel consumption.

Check of preliminary heating of air

Six-cylinder engine


  1. Dismantle the filter loose leaf.
  2. Look in a hose branch pipe if it is necessary, take a lamp.
  3. Depending on surrounding temperature the air zaslonka should close supply of cold or warm air.