Komatsu PC138USLC Operation & Maintenance Manual page 284

MAINTENANCE MAINTENANCE
1. Stop the engine.
2. Remove undercover (1) and cover (2) between the hydraulic
tank and operator's cab, then put a container in position to
catch the coolant.
3. Check that the cooling water temperature has gone down
enough to make it possible to touch the radiator cap surface by
hand, then turn radiator cap (3) slowly until it contacts the
stopper to release the pressure.
4. Following this, push radiator cap (3), turn it until it contacts the
stopper, then remove it.
5. Open drain valve (4) at the bottom of the radiator and drain the
water.
Remove drain plug (5) in the cylinder block and drain the water.
6. After draining the water, close drain valve (4) and tighten drain
plug (5), then fill with city water.
7. When the radiator is full, start the engine, and run it at low idle.
Keep the engine running at low idle for 10 minutes until the
water temperature reaches more than 90°C (194°F).
8. Stop the engine, then open drain valve (4) and remove drain
plug (5) to drain the water.
9. Close drain valve (4). Wind seal tapes onto drain plug (5), then
tighten it.
10. Install covers (1) and (2).
11. Fill with super coolant and tap water through the water filler up
to the bottom of the filler.
For details of the mix ratio for super coolant and water, see MIX
RATIO CHART FOR WATER AND SUPER COOLANT.
12. To bleed the air from the cooling system, run the engine at low
idle for 5 minutes, and for a further 5 minutes at high idle.
(When doing this, leave the radiator cap off.)
MAINTENANCE PROCEDURE MAINTENANCE PROCEDURE
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