E46 series BMW 3

since 1998 of release

Repair and car operation



E46 series BMW 3
+ BMW 3 Cars (Е46)
+ Current leaving and service
+ Engine
- Systems of cooling, heating
   - System of cooling of the engine
      Replacement of cooling liquid
      Thermoswitch check
      Check of system of cooling under pressure
      Connection and separation of the quick disconnect coupling
      Removal and thermostat installation
      Removal and installation of a fan / casing of the fan
      Removal and fan installation with the vyazkostny coupling
      Removal and radiator installation
      Removal and installation of the pump of cooling liquid
   + Heater and conditioner of air of salon
+ Power supply systems, injection and release
+ engine Electric equipment
+ RKPP and transmission line
+ Automatic transmission
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment
+ electric equipment Schemes



2d97642e


System of cooling of the engine

Scheme of a contour of cooling

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

6 — the block of cylinders
7 — return
8 — giving
9 — heating of a butterfly valve
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 — a krylchatka of the fan of a radiator
9 — the vyazkostny coupling


The engine is equipped with circulating system of cooling. While the engine is not heated-up, 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 cooling liquid the thermostat opens a big contour of cooling. Cooling liquid goes through a radiator constantly working pump. There is an innovation for the petrol engines, consisting in so-called cooling according to characteristics. Thus the control system of the engine regulates temperature of opening of the thermostat and optimizes, thus, engine temperature by criterion of fuel consumption.

Cooling liquid is filled in through a broad tank which is located sideways at a radiator and serves as capacity for liquid. It compensates the expansion of 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 cooling liquid to +93°С the thermoswitch connects the fan via the relay. If the temperature of cooling liquid falls below +89°С, the thermoswitch again switches off the fan.

The fan of a radiator can turn on at the idle engine. Owing to existence of thermal stagnation in an impellent compartment it can repeatedly occur. Therefore at 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 cooling liquid the additional krylchatka is established. In a nave the vyazkostny coupling settles down. As soon as the air going from a radiator, reaches temperature +90°С, the bimetallic plate in the vyazkostny coupling connects the fan. The fan rotates with turns of the engine and provides a necessary consumption of air until the temperature of cooling air will not fall to value +60°С. After that, the vyazkostny coupling is disconnected and reduces fan turns. Owing to changeably working fan useful engine capacity raises and fuel consumption decreases.