Coolant Replacement And Cleaning Of Cooling System; Draining Of Coolant - Mitsubishi 6M70 Workshop Manual

3. Coolant Replacement and Cleaning of Cooling System

Tightening torque (Unit: N·m {kgf·m})
Mark
– Radiator drain cock
– Crankcase drain cock
• Using the radiator for extended periods of time without cleaning can increase chance of rust and scale formation,
which may cause engine overheating. The cooling system must be cleaned periodically.
Use a coolant containing the FUSO DIESEL LONGLIFE COOLANT additive and soft water in the specified pro-
portions. (See the Owner's Handbook for instructions on the use of the additive.)

3.1 Draining of coolant

• Before draining the coolant, loosen the pressure cap to reduce the pressure in the cooling system. Remember to
drain the coolant out of the reservoir tank as well.
WARNING
• Drain the coolant only after it has cooled sufficiently to avoid getting scalded.
• Opening the pressure cap while the coolant temperature is still high can cause hot coolant to spray
out. Cover the pressure cap with a cloth, and loosen it slowly to let the pressure out before opening it
fully.
3.2 Cleaning procedure
CAUTION
• Water used for flushing the cooling system must be soft water that has a property meeting the require-
ments indicated below. Using hard water will cause scale and rust to form in the system.
Required properties of soft water
Total hardness .......................... 300 ppm or less
Sulfate SO .............................. 100 ppm or less
4
Chloride CI ............................. 100 ppm or less
Total dissolved solids .............. 500 ppm or less
pH .............................................. 6 to 8
• Keep the coolant temperature at approximately 90°C so that the thermostat valve remains open and coolant con-
tinues to circulate in the radiator.
• For the sake of convenience you can raise the coolant temperature quickly by covering the front of the radiator
with corrugated cardboard or something similar.
• In cases where a great amount of rust has accumulated it is common for the radiator to leak as a result of clean-
ing. Conduct a through check for leakage after cleaning.
• Select an appropriate cleaning method according to the condition of the cooling system as shown below.
Parts to be tightened Tightening torque
2.0 {0.2}
37 {3.8}
14
Remarks
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14-9