APRILIA SCARABEO 500 2008 Service Station Manual page 298

Cooling system
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Refit the water pump cover and tighten the six fixing screws to the prescribed torque.
Locking torques (N*m)
Water pump cover screws 3 ÷ 4
Water pump ceramic seal
Our fluid-cooled engines are fitted with water pumps made with this type of ceramic seal. This element
ensures coolant tightness at the pump shaft. The sealing is carried out by two ceramic surfaces, one
fixed and one moving, that are kept into contact with the pump shaft by the thrust of a coaxial spring.
Correct functioning is ensured by an accurate machining of the ceramic parts and adequate cleaning
of the components at the assembly stage, in any case the ceramic seals are mounted at an initial run-
in stage. During this first period of use (1000 ± 1500 km) there may be some little seeping through the
drainage holes that leave traces on the aluminium housing. This fact is particularly evident where the
drainage is more visible. If this occurs, clean the housing and then check tightness again for trips over
1500 km. If seeping persists or in case there are true leaks, replace the ceramic seal. To carry out these
operations, follow the procedures and use the appropriate tools indicated in the relevant service station
manuals.
diagnosis
Excessive system pressure
1 - Check the expansion tank cap efficiency.
NOTE
THE CAP IS PROVIDED WITH A PRESSURE RELIEF VALVE CALIBRATED AT 0.9 BAR.
There is also a valve that lets air in during the cooling stage.
YES - go to point 2 NO go to point 3
2 - Check the head gasket seal (see the «Thermal group and Timing system» chapter)
3. Replace the cap.
Cooling fluid consumption
1 - Check the system external seals as described above.
YES - go to point 2 NO go to point 3
2 - Check the head gasket seal (see the «Thermal group and Timing system» chapter)
- If water leaks are detected in the engine oil, inspect the buffer on the head cooling circuit.
3 - Fix any damaged seals.
Oil in the fluid
1 - There is oil in the coolant.
YES go to point 2
COOL SYS - 298
SCARABEO 500