Geely EC715 2009, Workshop Manual

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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 engine coolant flow amount
through the thermostat. This makes the engine warm up
quickly. Cooling system includes radiator, coolant recovery
reservoir, 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 to 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.
Coolant Recovery Reservoir is a transparent plastic container,
similar to the windshield washer tank. Coolant Recovery
Reservoir 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. 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 coolant recovery
reservoir.
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.
Master fan diameter is 310 mm (12.20 in), auxiliary fan
diameter is 270 mm (10.63 in), both have five blades. Cooling
fan assembly 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 has a 0.35 Ω current-
limiting resistor. When the engine coolant temperature reaches
95°C (203 ºF), the engine control module enables Low-Speed
cooling fan assembly operation, and when the engine coolant
temperature reaches 102°C (215.6 ºF), it enables the High-
Speed cooling fan operation. When the temperature is back to
97°C (206.6 ºF), the engine cooling fan control module will
switch the cooling fan from high to low, when the temperature
drops to 90°C (194 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 damage,
do not repair or reuse the damaged parts. The bent or
damaged fan blades must be replace. Damaged fan
blades can not guarantee the normal balance and
continuous use, and may fly off, which is very dangerous.
Warning!
As long as there is cooling system pressure, 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.
Engine Cooling System JL4G18-D 2-457
EC718/EC718RV EC715/EC715RV 10/2009