DAF CF65, CF75, CF85 Series . Manual — part 206

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200351

2-1

General

CE-ENGINE COOLING SYSTEM

ΧΦ65/75/85 series

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3

2. GENERAL

2.1 SYSTEM DESCRIPTION, COOLING SYSTEM

The cooling system consists of a water pump, a
radiator, a header tank, an oil cooler, an air
compressor, a thermostat housing with one
thermostat and pipes.

The water pump is located below the thermostat
in the engine block.
The thermostat housing is part of the cylinder
head.
From the delivery side of the water pump, the
coolant is directed to the oil cooler via an opening
at the back of the water pump. Afterwards the
coolant flows to the cylinder block.
The coolant flows through the cylinder block,
along the cylinder liners, and up to the cylinder
heads.

The coolant leaves the cylinder heads through
the thermostat housing.

Depending on the coolant temperature, the
thermostat distributes the coolant flow to the
radiator or back to the water pump.
The coolant transported to the radiator enters the
radiator at the top, and leaves the radiator at the
bottom.
From the bottom of the radiator, the coolant is
returned to the water pump, via the return pipe.

The connection pipe to the header tank is also
connected to the return pipe from the radiator.
When the coolant heats up, it flows to the header
tank. When the coolant cools down, it will flow
back from the header tank.

The oil cooler is not only intended to cool the
lubricating oil, but also to heat the lubricating oil in
a "cold" engine.

From the cylinder block, some of the coolant
flows through the air compressor.
From the air compressor, the coolant is returned
to the engine block via a pipe.

The pipe which takes the coolant to the cab
heater is connected to the cylinder head. From
the heater, the coolant is returned to the water
pump via a pipe.

M201133

M201134

CE-ENGINE COOLING SYSTEM

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200351

General

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ΧΦ65/75/85 series

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200351

3-1

Description of components

CE-ENGINE COOLING SYSTEM

ΧΦ65/75/85 series

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3. DESCRIPTION OF COMPONENTS

3.1 PRESSURE CAP

The pressure cap is fitted to the header tank by
means of a threaded connection.

The pressure cap has two valves: a pressure
relief valve (1) and a vacuum relief valve (2).

Overpressure
As a result of the rising coolant temperature, the
pressure in the cooling system will increase. If the
pressure in the cooling system becomes too high,
the pressure relief valve (1) will open against the
pressure of the spring.

Underpressure
If the coolant temperature drops, the pressure in
the cooling system will decrease. If the pressure
in the cooling system becomes too low, the
vacuum relief valve (2) will be opened.

2

1

A

B

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CE-ENGINE COOLING SYSTEM

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Description of components

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ΧΦ65/75/85 series

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3.2 THERMOSTAT

Operation, thermostat
Coming from the cylinder head, the coolant
passes through the thermostat. Depending on the
coolant temperature and the corresponding
position of the thermostat, there are three
possibilities:

Thermostat closed
The coolant has not yet reached the opening
temperature of the thermostat (1).
The supply channel (B) to the radiator is
completely closed.
The coolant flows directly to the water pump
through a bypass (A) and the water pump returns
the coolant to the cylinder block.

Thermostat starts opening
The coolant has reached the opening
temperature of the thermostat (1).
The supply channel (B) to the radiator is opened
and the bypass (A) is partially closed.
Now coolant will flow both through the supply
channel (B) to the radiator and directly to the
water pump through the bypass channel (A).

1

A

B

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1

A

B