FUSO 4M4 – HYBRID ELECTRIC VEHICLE SYSTEM – ON-VEHICLE INSPECTION AND ADJUSTMENT – Coolant Replacement of High Voltage Cooling System

• Open the radiator drain cock to drain coolant around the radiator.

• Disconnect the water hose (between the motor electronic control unit and the motor generator) of the motor electronic control unit.
• Coolant around the motor electronic control unit is drained.
• To drain coolant in the motor generator, apply air pressure to the water pipe on the motor generator side.

3.4 Filling and air bleeding

• After draining the coolant (or tap water if used for cleaning), fit the drain cock.
• Disconnect the water hose and remove the air bleeder on top of the motor generator.

• Turn up the end of the water hose.
• Pour coolant from the pressure cap port while performing actuator test No. A7 “Water pump ON” (automatically terminated in 10 minutes).

• When coolant comes out from the water hose, connect the water hose to the water pipe.

• When coolant comes out from the air bleeder port, fit the air bleeder.
• Pour the coolant up to the pressure cap port.
• Perform actuator test No. A7 “Water Pump ON” (automatically terminated in 10 minutes) twice so that coolant circulates through the cooling system for a total of 20 minutes for air bleeding.
• If the coolant level at the pressure cap port lowers, pour the additional coolant until the radiator is filled with coolant up to the brim of the pressure cap port. Then, fit the pressure cap.
• Remove the cap from the reservoir tank and pour coolant into it up to the “FULL” line.