Komatsu D31EX-21, Operation & Maintenance Manual, Page: 204 / 256

SERVICE PROCEDURE
MAINTENANCE
4-24
Mixing rate of water and antifreeze
q
D31EX,PX , D37EX,PX
q
D39EX,PX
WARNING
Antifreeze is flammable, so keep it away from flame.
Antifreeze is toxic. When removing the drain plug, be careful not to get water containing antifreeze on
you. If it gets in your eyes, flush your eyes with large amount of fresh water and see a doctor at once.
Use city water for the coolant.
If river water, well water or other such water supply must be used, contact your Komatsu distributor.
We recommend use of an antifreeze density gauge to control the mixing proportions.
q
Prepare a container to catch drained coolant minimum 40 liters capacity.
1. Stop the engine.
2. Turn radiator cap (1) slowly until it hits the stopper and by
so doing, relieving the internal pressure.
3. Turn radiator cap (1) until it hits the next stopper, while
depressing it. Keep turning the radiator cap (1) until it hits
the last stopper.
4. Place containers to catch the drained cooling water under
drain valve (2) at the bottom of the radiator and under drain
plug (3) at the bottom of the cooling water inlet port. Open
drain valve (2) and drain plug (3), and drain the water.
5. After draining the antifreeze solution, close drain valve (2)
and tighten drain plug (3), then fill with clean water. After
the radiator is filled with water, start and run the engine at
low idling speed. After the water temperature rises above
90°C, run the engine for about 10 minutes.
6. Stop the engine and open drain valve (2) and remove drain plug (3) to drain the water.
Min. atmospheric
temperature
°C Avobe -10 -15 -20 -25 -30
Amount of anti-
freeze
Liters 8.1 9.7 11.1 12.4 13.5
Amount
of water
Liters 18.9 17.3 15.9 14.6 13.5
Min. atmospheric
temperature
°C Avobe -10 -15 -20 -25 -30
Amount of anti-
freeze
liters 9.6 11.5 13.1 14.7 16.0
Amount
of water
liters 22.4 20.5 18.9 17.3 16.0