Geely Emgrand X7. Manual part — 134

Thermostat Type

Wax-Type Thermostat

Pump Type

Open impeller centrifugal pump

Blade Diameter

56 . 4mm

Blades 7

Thermostat Opening Temperature 82 (179.6 )

℃

℉

Thermostat Fully Opening
Temperature

95 (203 )

℃

℉

Low Speed Cooling Fan Turned On

95 (203 ºF)

℃

Low Speed Cooling Fan Turned Off

92 (197.6 ºF)

℃

High Speed Cooling Fan Turned On

98 (208.4 ºF)

℃

High Speed Cooling Fan Turned Off 95 (203 ºF)

℃

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2.8.2 Description and operation

2.8.2.1 Description and operation

When engine is working, the mixture combustion in the cylinder combustion chamber produces
heat, which transfers through the cylinder block. If it is not cooled, the engine will not work.
Inside the cylinder block, there is engine coolant path. Through the engine coolant flow, heat
exchanges with the outside environment. This keeps the engine operating temperature within a
certain range, so that the engine can work effectively in all operating conditions. When the engine
is cooled, the cooling system controls the flow amount of engine coolant through the thermostat.
This makes the engine warm up quickly. Cooling system includes radiator, expansion tank,
cooling fan assembly, thermostat and housing, water pump and water pump drive belt. The water
pump is driven by the accessory drive belt. Only when all the above components work properly,
can the cooling system work properly. When the engine coolant reaches the thermostat operating
temperature, the thermostat opens. At this point, the engine coolant returns to the radiator and gets
cooled. Cooling system guides part of the engine coolant through the pipes into the heater core.
Used for heating and defrost. Coolant Recovery Reservoir is connected to the radiator assembly
for recycling discharged engine coolant, which is expanded due to the heat. The Coolant Recovery
Reservoir is to maintain the correct engine coolant level.

Expansion tank is a transparent plastic container, similar to the front windshield washer tank.
Expansion tank assembly connects to the engine cooling system and the radiator through two
separate pipes. With the vehicle driving, the engine coolant temperature gradually increases and
the coolant expands. Part of the engine coolant flows from the radiator into the coolant recovery
reservoir as the result of expansion. Resident air in the radiator and engine is also expelled to the
Coolant Recovery Reservoir. When the engine is shut down, the engine coolant cools down and
contracts, previously discharged engine coolant flows back to the radiator and the engine. This
makes the engine coolant radiator maintain a suitable coolant level, and improves cooling
efficiency. When the cooling system is cold, the engine coolant level should be kept between the
MIN (minimum) and MAX (maximum) marks in the expansion tank.

Cooling fan assembly is installed at the rear of the radiator in the engine compartment. It increases
radiator and Air- Conditioning condenser air flow, and thus help accelerate the cooling when
idling or at low speed. There are dual fans, high or low speed control modes controlled by two
different motors. Cooling fan is controlled by the engine control module (ECM) using Low-Speed
cooling fan relay and high speed cooling fan relay. In the Low-Speed circuit, the series connection
is used to change the fan speed. When the engine coolant temperature reaches 95°C (203 °F), the
engine control module enables Low-Speed cooling fan assembly operation, and when the engine
coolant temperature reaches 98 (208.4

℃

°F), it enables the High- Speed cooling fan operation.

When the temperature is back to 95 (203 ºF), the engine control module will switch the cooling

℃

fan from high to low, when the temperature drops to 92 (197.6 ºF), the fan will be off.

℃

Warning: Even if the engine is not running, the cooling fan under the engine compartment
may still start and cause injury. Keep hands, clothing and tools away from the cooling fan
under the engine compartment.

Warning: If there is any degree of fan blades bending or damaging, do not repair or reuse
the damaged components. The bent or damaged fan blades must be replaced. Damaged fan
blades can not guarantee the normal balance and continuous use, and may fly off, which is
very dangerous.

As long as there is pressure in the cooling system, even though the solution in the radiator is
not boiled, the solution temperature will be much higher than the water boiling point. If the
engine is not cooled and the pressure is still high, and the pressure cover is opened, the
engine coolant will be immediately boiled and will spray onto the engine, fenders and the
person opening the radiator pressure cap.

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2.8.3 System operating principle

2.8.3.1 System operating Principle
Cold Engine: the engine normal operating temperature is generally around 95°C (203 °F), in this

temperature range, all the engine parts running status will be ideal. If the engine can not reach the

ideal operating temperature in a long time,it will increase the parts wear and tear. Because of low

temperature, the mixture combustion will be inadequate, and there will be excessive carbon

residue. The engine heat exchange must be kept minimum so the engine can reach normal working

temperatures in a short period of time. At this point the thermostat controls the engine coolant only

circulates within the engine block, bringing the heat from the cylinder wall to the other engine

parts, so that the temperature increases rapidly. Water pumps makes the engine coolant flow in the

cylinder block, then in the engine block water jacket, throttle body and cylinder hood cover. This

is called "small loop".
Engine at normal working temperature: With the engine running, the engine coolant temperature

quickly increases, when the thermostat reaches 83 (181.4

℃

°F), the engine coolant is drawn into

the engine block water jacket, intake manifolds, cylinder hood and radiator by the water pump.

This is called "big loop".
Thermostat: the thermostat is used to control the flow of engine coolant in the cooling system.

Thermostat is installed in the front of the engine and sealed by the engine intake pipe joints

components, located in the front of the cylinder hood cover. The thermostat can prevent the engine

coolant.
Flow from the engine to the radiator, so as to rapidly pre-heating the engine and adjust the

temperature of engine coolant. When the engine coolant temperature is low, the thermostat in the

closed position, preventing the engine coolant circulating through the radiator. Starting is only

allowed at this time.
Engine coolant is circulated through the heater core to quickly and uniformly preheat the engine.

When the engine is warm, the thermostat opens. The engine coolant flows through radiator and

exchanges the heat. Thermostat opening and closing, allow sufficient engine coolant to enter into

the radiator, maintaining the engine at normal operating temperature range. The wax ball inside

the thermostat is sealed in a metal casing. Thermostat wax ball thermal expands when warm and

contracts when cold. As the vehicle drives and the engine warms up, engine coolant temperature

increases. When the engine coolant reaches the required temperature, the thermostat wax ball

expands, puts pressure on the metal shell and opens the valve. This allows the engine coolant to

flow through the engine cooling system and engine to cool down, when the wax ball contracts,

under the action of the spring, the valve will be closed.

Cooling Fan Low-Speed Circuit Description: Engine cooling fan circuit controls the main cooling

fan and auxiliary cooling fan. Cooling fan is controlled by the engine control module (ECM)

according to the temperature sensor of engine coolant and air pressure switch inputs.
When ECM monitors conditions that meet the cooling fan Low-Speed running conditions, ECM

controls the engine wiring harness connector EM01 terminal No.65 for internal grounding, and the

Low-Speed cooling fan relay pulls in. Power passes through the low speed relay 1 terminal No.87

to reach the cooling fan motor 1 and then through the Fan low-speed relay 2 to reach the fan motor

2 within the series connection. Finally the circuit is grounded via the harness connector CA10

terminal #2 of fan motor 2. For the series connection of the fan motors changes the current

through the motors, the fan motors run at low speed.
Description of high-speed circuit of cooling fan: the engine control module receives the engine

coolant temperature sensor and air-conditioning pressure switch signal; after reaching the

condition that the cooling fan rotates at high speed through the calculation of the internal program,

the ECM controls the terminal 17 of the engine wire harness connector EM01 to internal ground;

at this time, the cooling fan high-speed relay and the low-speed relay 2 are closed; the power

supply of the fan 2 reaches the terminal 1 of the wire harness connector CA10 of the cooling fan 2

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The themostat start to open when the tem-

perature of engine coolant reach to 83℃(181.4ºF), and it fully opened when the temperature at
95℃(1203ºF)

from the terminal 87 of the high-speed relay and is grounded through the terminal 2 of the wire
harness connector CA10 of the cooling fan 2; at the same time, as the low-speed relay 2 is closed,
the power supply of the fan 1 reaches to the cooling fan motor from the terminal 87 of the
low-speed relay 1 and then is grounded through the terminal 87 of the closed low-speed relay 2.
The circuits of the fan motor 1 and motor 2 are connected in parallel from in series, so that the fan
motor rotates at a high speed.

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