Excessive pressure and radiator fan. Mercedes-Benz E-Class

REPAIR MAINTENANCE OPERATION OF MOTOR VEHICLES
Mercedes-Benz E-Class

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Fig. 4.41. Check the expansion tank cap: 1 - a cover of a broad tank; 2 - Pump

The cooling system is pressurized. Thereby, and by the addition of antifreeze boiling point of the coolant is increased to +126 ?� C. The higher temperature promotes a more economical operation of the engine. The pressure in the cooling system is about 1.4-1.5 bar. If the engine is hot pressure rises to the higher value, the pressure reducing valve is triggered in the expansion tank cap (fig. 4.41). If overheating further turns on the fan.

Engines equipped with a fan with viscous coupling or motor. These units comprise from bimetal thermoswitch that if the temperature of the flowing fluid exceeds a certain value. The switch turns off the fan when the coolant temperature is lowered to a safe level.

A WARNING

The fan and radiator can be switched with the ignition off due to aerodynamic heating of the engine.

Technical Dictionary

Components of the cooling system

Water Pump. A centrifugal pump to circulate the coolant. In the 4-cylinder engine water pump located on the same shaft as the fan. At 6-cylinder engine water pump is mounted on the left side of the engine 4 bolts.

Radiator. All radiators are made of light alloy. Radiators as fan shroud have different dimensions. On vehicles with automatic transmission at the right water tank drain valve mounted radiator coolant.

Thermostat. This depends on the temperature controller controls the coolant circuit.

Circuit at C to +85 ?�: the coolant is circulated through the small loop.

Circuit normal operation at temperatures 85 ... 100 ?� C: partially opens the radiator; cold liquid from the radiator is mixed with the warm coolant before it is supplied to the pump motor.

Maximum cooling at temperatures above +100 ?� C: The thermostat valve is fully open, all of the coolant passes through the radiator.

Expansion tank. Bleed steam in the event of excess pressure via a pressure reducing valve in the lid.

The radiator fan. Depending on the engine, as well as the vehicle's equipment, installed fan with viscous coupling or motor.

Additional fan

If your car is equipped with air conditioning, the front of the radiator is equipped with two connected to each other by the fan belt, and the fan on the left, is equipped with an electric motor, which also operates the right fan.