Gilera 633721, Workshop Manual

Page: 330 / 407

- Select the menu on the "ACTIVE DIAGNOSIS"
function and start the electric fan operation simu-
lation (see "Injection" chapter).
- If the electric fan is certainly efficient, check the
ventilation start and stop temperatures.
- Select the «PARAMETERS» function in this
menu to display the coolant temperature.
Electric fan starts: 107°C
Electric fan stops: 103°C
- If non-conforming values are detected, replace
the injection control unit (see «Injection» Chapter).
- If the analogue instrument temperature is close
to the red zone, but the degrees indicated by the
diagnostic tester are below the electric fan start
temperature, check the temperature sensor on the
head and the relevant injection circuit (see «Injec-
tion» chapter);
N.B.
THE ELECTRIC FAN TEMPERATURE AT 107° C CAN ONLY BE MANAGED BY A SYSTEM SUP-
PLIED WITH A 50% MIXTURE AND PRESSURISED AT 0.9 BAR.
AVOID STARTING THE ENGINE WITHOUT PRESSURISATION SINCE IT MAY REACH THE BOIL-
ING TEMPERATURE BEFORE THE ELECTRIC FAN STARTS WORKING.
IN CASE OF AN INCREASE OF THE ELECTRIC FAN START TIME, CHECK THE THERMOSTAT
OPENING TEMPERATURE AND CHECK THAT THE COOLANT DENSITY IS CORRECT. THE OP-
TIMUM DENSITY IS OBTAINED WITH A 50% WATER / 50% COOLING CIRCUIT FLUID MIXTURE.
System sealing check
- Check the proper circuit sealing when it is under
pressure and at the temperature.
- For a more accurate check, wait until the system
has cooled down since small leaks may not be
visible due to evaporation
- The water pump is provided with a drainage hole
in case of leaks from the cooling system mechan-
ical seal, or from the shaft sealing oil guard.
- If coolant or oil leaks are detected, inspect the pump (see Flywheel cover chapter).
N.B.
Cooling system
Nexus 500 euro 3
COOL SYS - 330