Cooling system device (VW Golf 2)

The cooling system diagram is shown in Figure 2.1.



The cooling system in Golf and Jetta vehicles is a pressurized cooling system and consists of:

• Radiator 2, located in the front of the car with an electric fan.
• Water pump 4, screwed to engine body 1.
• Coolant pump 9 turbocharger 8 (if any).
• Thermostat 10, which switches off the radiator from the circulation of coolant.
• There are 3 heaters that heat the car's interior.
• Engine oil radiator 7.
• Automatic transmission oil cooler 6 (if any).
• Equalizing tank 5.
• The outlet nipple 11, screwed to the head above the flywheel. The outlet nipple 12, screwed to the head from the spark plug or injector side
• Thermal switch of radiator fan 14 (Fig. 2.3). Coolant temperature sensor.
• Flexible and metal connecting pipes. The radiator has a structure made of aluminum. This is a set of tubes connected by radiator plates, facilitating the transfer of heat to the air passing through the radiator. Radiator plates strengthen the radiator structure and increase its useful area.

The fan is mounted on the radiator using a casing 9 made of tin. The fan consists of a plastic propeller 7 and an electric motor 8 that drives it (figure 2.2). It forces air through the radiator, especially when the car is moving at low speeds, such as on a city street. The signal that turns on the radiator fan is the temperature of the coolant.





If the coolant temperature rises above 93-98°C, the thermal switch 11 will turn on the fan. If the coolant temperature drops to 88-93°C, the same thermal switch will turn off the fan. The coolant temperature sensor is connected by an electric wire to the temperature gauge on the instrument panel. It informs the driver of the coolant temperature at the current time.

Water pump 4 (figure 2.1) has a standard design and is driven by the crankshaft. In 1.1 and 1.3 engines, the water pump is driven by a timing belt, and in 1.6 and 1.8 engines, by a V-belt. The water pump serves to force water circulation in the cooling system. Cooling with forced circulation makes it possible to remove a large amount of heat. An engine with such a system can operate with a greater load and have a higher compression ratio. In engines equipped with a turbocharger 8, an electric coolant pump 9 is additionally mounted in the system. It forces the coolant to pass through the turbocharger when the coolant temperature in the turbocharger exceeds 105°C. This can happen, for example, after turning off a hot engine, when the main pump stops working. The flow of coolant through the radiator is regulated by a thermostat, the location of which may vary depending on the engine type. In 1.1 and 1.3 liter engines (figure 2.4) thermostat 5 is located in housing 3, screwed to the rear of the engine head below the ignition mechanism. In engines 1.6 and 1.8 (figure 2.5) thermostat 3 is located at the base of the water pump housing, mounted below the front of the engine (from the timing belt shield side).






The heater is located inside the passenger compartment, which is what heats it. To regulate the amount of liquid circulation through the heater, a so-called heater valve is used, which is controlled from inside the car (see section "Body"). An engine with fuel injection or turbocharger has an oil cooler 7 (figure 2.1), which is cooled by water from the cooling system.

The oil cooler is located between the oil filter and the oil filter crown and is bolted to the engine body.

Surge tank 5 (figure 2.1) located in the engine compartment. In some models, it is equipped with a coolant level sensor. The equalizing tank is connected by a rubber hose to the return pipe (stove-water pump).

In cars with automatic transmission and turbocharging, a gear oil cooler is installed 6 (figure 2.1). The idea is that, when high power is developed, the oil's stickiness does not fall below the limit after which the correct operation of the gears is reduced.

[The original article is posted on the website: www.VWMANUAL.ru]