Komatsu ecot3 Operation And Maintenance Manual page 293

MAINTENANCE PROCEDURE MAINTENANCE PROCEDURE
13. Drain the coolant from sub-tank (4), clean the inside of the
sub-tank, then add coolant until the coolant level is between
the FULL and LOW marks.
If the sub-tank is extremely dirty and it is difficult to clean,
replace it with a new part.
14. Stop the engine, wait for approximately 3 minutes, add coolant
up to the mouth of the filler port, and tighten the radiator cap (2).
15. Close engine hood (1).
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MAINTENANCE MAINTENANCE