DAF CF65, CF75, CF85 Series . Manual — part 233

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Description of components

PE ENGINE COOLING SYSTEM

CF65/75/85 series

2

6

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

M201036

PE ENGINE COOLING SYSTEM

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Description of components

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CF65/75/85 series

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3.2 DESCRIPTION OF THERMOSTAT

Operation, thermostat
The coolant enters the thermostat housing

directly from the coolant collector pipe at the back

and flows 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 thermostat

opening temperature.

The supply channel (B) to the radiator is

completely closed.

The coolant flows directly to the coolant pump

through a bypass (A) and the coolant pump

returns the coolant to the cylinder block.

B

M200739

A

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Description of components

PE ENGINE COOLING SYSTEM

CF65/75/85 series

2

6

Thermostat starts opening

The coolant has reached the thermostat opening

temperature.

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 through the

bypass (A) directly to the coolant pump.

Thermostat fully opened

The temperature of the coolant has further

increased. The supply channel (B) to the radiator

is fully opened and the bypass channel (A) is fully

closed.

The entire coolant circulation now flows via the

supply channel (B) to the radiator where it is

cooled before flowing back to the coolant pump.

In the event of excessive coolant temperatures,

removing the thermostat as an emergency

solution is not permitted.

If the thermostat is removed from the engine,

uncooled coolant will flow to the coolant pump

through the bypass (A). As a result, the coolant

temperature will continue to rise.

B

M200740

A

B

M200741

A

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Description of components

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CF65/75/85 series

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3.3 COOLANT FILTER

The task of the coolant filter is to filter the coolant

to prevent cavitation. The coolant filter is

necessary when the cooling system is filled with

low-quality coolant.