FUSO 4M4 – COOLING – ON-VEHICLE INSPECTION AND ADJUSTMENT – Coolant Replacement and Cleaning of Cooling System

• 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.

3.1 Draining of coolant

• Before draining the radiator, slowly loosen the pressure cap covered with a shop towel or the like and lower pressure in the cooling system while coolant is cool enough. Remember to drain the coolant out of the reservoir tank as well.

3.2 Cleaning procedure

• Keep the coolant temperature at approximately 90°C so that the thermostat valve remains open and coolant continues 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 cleaning. Conduct a through check for leakage after cleaning.

• Select an appropriate cleaning method according to the condition of the cooling system as shown below.


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