Nanni Diesel H4.115 Manuel D'utilisation page 29

Seawater valve is closed
Seawater fi lter is clogged
Seawater pump is sucking air
Coolant circuit pump belt is slack or faulty
Coolant pump is faulty
Seawater pump rotor is faulty
Insuffi cient coolant
Thermostat is malfunctioning
Cooling system is blocked
Closed cooling circuit is dirty
Loss of pressure in the closed cooling circuit
Coolant is unsuitable
29
Faults and probable causes
Engine overheats / Engine coolant temperature too high
Faults
Open the seawater valve
Close the seawater valve and clean the fi lter
Check the position and seal of the seawater fi lter cover
and the suction hose
Re-tighten or replace the belt
Replace the pumpe and the belt
Replace the rotor
Fill with coolant and check that the cooling system is leak-
tight
Replace the thermostat
Locate the problem and clean
Clean and rinse
Check there are no leaks. Clean, inspect and check the
fi ll cap
Use the recommended coolant (see technical
specifi cations)
Solution
Dépannage