DAF CF65, CF75, CF85 Series . Manual - part 208

 

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DAF CF65, CF75, CF85 Series . Manual - part 208

 

 

©

 200351

4-1

Inspection and adjustment

CE-ENGINE COOLING SYSTEM

ΧΦ65/75/85 series

2

3

4. INSPECTION AND ADJUSTMENT

4.1 PRESSURE TESTING

}

When the coolant is hot, there is 
overpressure in the cooling system. 
Carefully remove the filler cap to 
release the overpressure. Coolant is 
a toxic fluid. Contact with the skin 
should therefore be avoided. To 
avoid damaging the cylinder block; 
do not top up a warm engine with 
cold coolant.
If this is done when the engine is 
warm, any cracks can be spotted 
more quickly.
The cooling system can be checked 
for leaks with a pressure-test pump.

1.

Open the grille.

2.

Remove the filler cap.

3.

Fill the cooling system to the correct level.

4.

Raise the engine temperature. This need not 
be the operating temperature.

5.

Fit a pressure-test pump. Pressure-test the 
system at the specified pressure. See 
"Technical data".

6.

Check for leakage.

M201192

CE-ENGINE COOLING SYSTEM

4-2

©

 200351

Inspection and adjustment

3

ΧΦ65/75/85 series

2

4.2 INSPECTION, THERMOSTAT

1.

Remove the thermostat. See "Removal and 
installation".

2.

Inspect the sealing surfaces of the 
thermostat housing for damage.

3.

Check the thermostat seat for damage.

4.

Check whether the thermostat is fully closed.

5.

Place the thermostat in a container filled with 
clean water.

6.

Place a thermometer in the container and 
heat the water. Check at which temperature 
the thermostat opens and whether it opens 
fully. See "Technical data".

M200513

©

 200351

4-3

Inspection and adjustment

CE-ENGINE COOLING SYSTEM

ΧΦ65/75/85 series

2

3

4.3 INSPECTION, VISCOUS FAN CLUTCH

}

Do not run the engine in an enclosed 
or unventilated area. Make sure 
exhaust fumes are properly 
extracted. Remain at a safe distance 
from rotating and/or moving 
components.

During this test, the slip in the viscous fan clutch 
is measured while the clutch is not operating. 
This test must be carried out when the engine is 
"cold" (coolant temperature approximately 50

|C).

Testing with a cold engine
1.

Check the coolant level, and top up as 
necessary.

2.

Start the engine and run it at idling speed for 
at least 5 minutes.
Then use an optical rev counter to measure 
the fan speed at different engine speeds 
(from idling to maximum engine speed). 
During this test procedure, the speed of the 
fan should be approx. 600 to 1100 rpm.

This test checks whether the bimetallic strip starts 
opening the valve at an operating temperature of 
85 - 95

|C.

Testing with a warm engine
1.

Check the coolant level, and top up as 
necessary. Be careful when topping up the 
coolant of a warm engine.

CE-ENGINE COOLING SYSTEM

4-4

©

 200351

Inspection and adjustment

3

ΧΦ65/75/85 series

2

2.

Take a sheet of cardboard with a 100 mm 
hole, as shown in the drawing opposite, and 
place it in front of the radiator, with the hole 
in front of the viscous clutch.

3.

Check that the gearbox is in neutral.

4.

Bring the cooling system to operating 
temperature.

5.

Allow the fan drive flange to run at a speed of 
1000 rpm. Then use an optical rev counter to 
determine the difference between the 
rotating speeds of the fan and the drive 
flange. The speeds will differ as a result of 
slip in the viscous clutch. When the clutch is 
fully engaged, the slip must not exceed 10%. 
If it is more, the viscous fan clutch must be 
replaced.

100

550

450

750

300

M201166

 

 

 

 

 

 

 

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