VDL Futura FHD2 E6, Workshop Manual, Page: 78 / 184

0
Futura FHD2/FMD2 E6
DIAGNOSIS
Systems
2 - 10
2
DD1020_01
2.4 COOLING SYSTEM
2.4.1 THE ENGINE TEMPERATURE RISES
2.4.2 CONSTANT BRAKING WHEN THE INTARDER IS
TURNED OFF
Possible cause Remedy
Faulty intake system. Check the intake system.
Incorrect poly V-belt tension. Check the poly V-belt tension. If necessary, replace the
poly V-belt or the poly V-belt tensioner.
The coolant level is too low. Check the coolant level. If necessary, top it up.
A coolant hose is cracked or blocked. Check/clean the coolant hoses.
The cooling system’s intercooler and radiator are con-
taminated. Check/clean the cooling system’s intercooler and radia-
tor.
The waste-gate setting too high. Check the waste-gate setting.
The turbo compressor housing’s air hose to the waste-
gate diaphragm leaks or is not connected. Check the air hose. If necessary, replace it.
The pressure cap is faulty or does not work. Check the pressure cap.
The thermostat opens insufficiently or does not open. Check the thermostat and its operation.
The coolant filter is contaminated. Check the coolant filter. If necessary, replace the filter
and clean the cooling system.
The wrong type of thermostat is fitted. Check the thermostat and its operation.
The coolant pump is faulty. Check the coolant pump’s shaft, bearings and fan. If nec-
essary, replace the coolant pump.
The fan drive is faulty. Check the fan drive.
The temperature control is faulty. Check the coolant temperature sensor.
Check the control flow’s return control at a high temper-
ature.
Too high intarder pressure when the intarder is turned
off. See the fault finding table: “Constant braking when the
intarder is turned off, cooling system”
2 - 2.4.2 Constant
braking when the intarder is turned off (

2 - 10)
Possible cause Remedy
Too much oil in the gearbox. Drain the excess oil.
The control pressure does not drop. Check the retarder’s control pressure when the retarder
is turned off.
The volume control valve does not return to the rest posi-
tion. Check the operation of the volume control valve.