BMW 7_aya the E38 series from 1994 to 2002
1. Introduction
2. Governing bodies and methods of operation
3. Settings and routine maintenance of the car
4. Engine
5. Cooling systems of the engine, heating, ventilation and air conditioning
5.1. Engine cooling system
5.2. Systems of heating, ventilation and air conditioning
5.2.1. General information
5.2.2. Removal and installation of a heater
5.2.3. Removal and installation of a radiator of a heater
5.2.4. Removal and installation of fans and resistor assemblies
5.2.5. Removal and installation of the additional water pump and water valve
5.2.6. Removal and installation of deflectors of systems of heating, ventilation and To/in
5.2.7. Removal and installation of the K/V compressor
5.2.8. Removal of other components of the K/V system
6. A power supply system and production of the fulfilled gases
7. Systems of electric equipment of the engine
8. Manual box of gear shifting and coupling
9. Automatic transmission
10. Cardan and power shafts, reducer, differential and stupichny assemblies
11. Brake system
12. Suspension bracket and steering
13. Body
14. Onboard electric equipment
15. Schemes of electric equipment


5.2.1. General information

General information

Description of systems

The description of management of system of ventilation with a heater and To/in is provided in the Head Governing bodies and methods of operation.

The cooling liquid heated in the engine is passed via the heat exchanger, giving to the air which is warmly passing through it. Air supply in salon is regulated by gates. If to turn on the heater fan, air will move in salon more intensively. Speed of the fan can be regulated. At the closed OZh gate comes on a small contour back to an engine radiator contour.

Before getting to salon, air passes through the filter in which the main share of dust settles. It is necessary to observe frequency of replacement of the filter since the filter blocked by dust limits air supply that will lead to an air stagnation in salon.

Distribution of streams of air of system of ventilation is carried out also by means of gates. On all models the air circulation mode is provided.

The air conditioning system (K/V) is installed as the additional equipment.

Works with the K/V system have to be performed in a specialized workshop. Do not open a coolant circulation contour as at contact with skin coolant can cause a frostbite.

By means of the K/V system air temperature in salon can be lowered rather external temperature. Besides during the work of the K/V system humidity of air in salon decreases.

In system R134a coolant which depending on temperature and pressure, can be in liquid or gaseous state circulates.

Function chart of the K/V system

1 — the Fan
2 — the Evaporator
3 — the Broad valve
4 — the Dehumidifier
5 — the condenser Fan
6 — the Condenser
7 — the Compressor
a — External air

b — Heated air
with — Warm external air
d — the Cooled external air
A — the Contour of high pressure, gaseous coolant
B — the Contour of high pressure, liquid coolant
With — the Contour of low pressure, liquid coolant
D — the Contour of low pressure, gaseous coolant

The compressor of the conditioner is given by a belt from a bent shaft of the engine and creates pressure in a contour of the coolant representing gas. At the same time coolant heats up. In the condenser coolant is cooled with external air. Thereof the warmed coolant passes into a liquid phase. Then under high pressure coolant is passed via the broad valve therefore pressure of coolant falls. After that coolant evaporates in a contour, at the same time strongly being cooled. In the evaporator coolant selects heat from the air blown through it. Thereof air is cooled and comes to interior of the car. As a result of heating in the evaporator coolant turns into gas and under low pressure comes to the compressor then process of circulation repeats.

Compressor oil which circulates in system together with coolant is applied to lubricant of components of the K/V system.

Security measures at service of the K/V system

Service of the K/V system should be charged to exclusively prepared technicians trained in safe working methods with use of the appropriate equipment and with observance of rules of depressurization and also acquainted with methods of collecting and storage of automobile coolant.

  • Do not allow contact of coolant with skin;
  • During the work near the K/V system put on goggles;
  • At hit of coolant on skin or in eyes do not pound the struck place. Immediately wash out an affected area cold water within not less than 15 minutes and ask for the qualified medical care. Self-treatment is not allowed;
  • Coolant is stored in cylinders under pressure. You store a cylinder at a temperature not above the 50th hail. Take the measures excluding falling of a cylinder about heights or other situations which can lead to its damage;
  • Works should be carried out in well aired room. Coolant quickly evaporates, leads to reduction of access of oxygen and difficulty of breath;
  • Gaseous coolant is heavier than air and rather quickly has to gather below, for example, under the car;
  • At combustion of coolant poisonous gas is formed. You store coolant far from open sources of fire. You do not smoke at work with the K/V system;
  • When carrying out welding works near the K/V system do not subject to its influence high temperature or an open flame. The overheat can lead to increase in pressure in system and to ignition;
  • Cleaning of the condenser or evaporator by means of water vapor is not allowed. It is necessary to use only cold water or compressed air.

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5.2.2. Removal and installation of a heater