BMW 3 series E46

Since 1998 of release

Repair and car operation



The BMW of 3 series Е46
+ Cars BMW 3 (Е46)
+ Current leaving and service
+ The engine
- Systems of cooling, heating
   - System of cooling of the engine
      Replacement of a cooling liquid
      Thermoswitch check
      Check of system of cooling under pressure
      Connection and separation quick disconnect муфты
      Removal and thermostat installation
      Removal and installation of the fan / of a casing of the fan
      Removal and installation of the fan with вязкостной муфтой
      Removal and radiator installation
      Removal and installation of the pump of a cooling liquid
   + Heater and the conditioner of air of salon
+ Power supply systems, injection and release
+ Engine electric equipment
+ РКПП and трансмиссионная a line
+ Automatic transmission
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment
+ Electric equipment schemes


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System of cooling of the engine

The scheme of a contour of cooling

1 — a radiator
2 — a broad tank
3 — salon heating
4 — the thermostat
5 — the pump of a cooling liquid

6 — the block of cylinders
7 — return
8 — giving
9 — heating throttle заслонки
10 — the heater crane


Elements of system of cooling

1 — a radiator
2 — the bottom hose of a radiator
3 — the top hose of a radiator
4 — a radiator stopper
5 — the water pump

6 — the thermostat
7 — the thermostat case
8 — крыльчатка the radiator fan
9 — вязкостная муфта


The engine is equipped by circulating system of cooling. While the engine is not heated-up, the cooling liquid circulates only in a head and the block of cylinders and at the open crane of a heater in the heat exchanger of a heater of salon. At increase of temperature of a cooling liquid the thermostat opens the big contour of cooling. The cooling liquid goes through a radiator constantly working pump. There is an innovation for the petrol engines, consisting in so-called cooling under characteristics. Thus the control system of the engine regulates temperature of opening of the thermostat and optimises, thus, engine temperature by criterion of the expense of fuel.

The cooling liquid is filled in through a broad tank which is located sideways at a radiator and serves as capacity for a liquid. It compensates the expansion of a liquid arising owing to its heating, and gives the chance to it to decrease in volume after engine cooling.

For increase of efficiency of cooling in system the fan operated depending on temperature is established. At increase of temperature of a cooling liquid to +93С the thermoswitch connects the fan through the relay. If the temperature of a cooling liquid falls more low +89С, the thermoswitch again switches off the fan.

The radiator fan can join at the idle engine. Owing to presence of thermal stagnation in an impellent compartment it can repeatedly occur. Therefore at performance of works around the fan wait, while the engine will be cooled.


320i, 323i, 328i with the conditioner: For increase of efficiency of cooling on a shaft of the pump of a cooling liquid it is established additional крыльчатка. In a nave settles down вязкостная муфта. As soon as air going from a radiator, reaches temperatures +90С, the bimetallic plate in вязкостной муфте connects the fan. The fan rotates with turns of the engine and provides the necessary expense of air until the temperature of cooling air will not fall to value +60С. After that, вязкостная муфта it is disconnected and reduces fan turns. Owing to changeably working fan useful capacity of the engine raises and the fuel expense decreases.