Group 22
Coolant, filling
To ensure excellent cooling of the engine, it is vital to check that the correct coolant volume is added when coolant is being replaced. Coolant levels that are too low can cause the engine to be damaged due to overheating (piston seizure).
Since the coolant volume varies between various engine types and installations, we recommend that a sufficient volume of coolant (fresh water with glycol, or anti-corrosion additives) is mixed in a container before filling. This process assures that the correct volume of coolant is added to the engine and that no air-pockets remain in the system.
See current Instruction Book/Workshop manual regarding coolant volumes and filling/venting the cooling system.
Note that if there is a heating plant, water heater or equivalent connected to the engine cooling system, a commensurately larger volume of coolant is required. There may also be additional vent cocks.
Filling must not be done so fast that air is locked in the system. The air must be able to pass out through the filler opening.
Filling should be carried out with the engine stopped. The engine must not be started until the system has been vented and completely filled.
If a heater system is connected to the engine’s cooling system, the heat control valve should be fully opened and the heater system vented during filling.
Flush clean the cooling system before filling with coolant.
Check all hoses and connections and fix any leaks. Close the drain cocks.
Fill with coolant to the correct level, see “Checking coolant level”. Check that the cooling system is properly vented by carefully opening the venting cock after the engine has been started and has reached operating temperature. Any remaining air must be removed. The engine must not be started until the system has been vented and completely filled.
Service procedures - cooling system
On engines with a separate expansion tank (optional equipment), the filling of large volumes is done directly through the filler opening on the radiator, until the system is vented and completely filled. Close the venting cock, screw on the filler cap and finally fill the separate expansion tank to between the MIN and MAX marks.
Coolant temperature too high
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Too high coolant temperature can be caused by:
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Low coolant level, air in the system
Reduced air flow through the radiator, dirty radiator
Poor drive belt tension
Blocked cooling system
Faulty thermostat
Faulty temperature gauge
Faulty setting of injection pump with regard to the preinjection angle
Coolant temperature too low
Too low coolant temperature can be caused by:
– Faulty thermostat
– Faulty temperature gauge
Temperature gauge, checking
Remove the temperature sensor. Connect the cables to the temperature gauge and immerse the sensor in hot water.
Compare the temperature gauge reading with that of a thermometer.
WARNING! Do NOT open the pressure cap (bleed cock) when the engine is hot. Steam or hot coolant can spray out and the system pressure will be lost.
The pressure loss means that circulation in the system can be impaired, leading to overheating and engine damage. Hot fluids and hot surfaces can cause burns.
1
Remove the level switch
WARNING! Remove the level switch very carefully when the engine is hot. Steam or hot coolant can spray out.
2
Place a plug M10 x 1 in the hole in the expansion tank.
Topping-up should be carried out with the same mixture as is already used in the cooling system.
3
Clean the tip of the switch if it is oxide coated. Connect the wire to the switch, (the switch must not be connected to engine body, ground).
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