Komatsu PW130ES-6K Operation & Maintenance Manual page 191

SERVICE PROCEDURE
cool until the radiator filler cap is cool enough to touch
with your hand. Remove the filler cap slowly to allow
pressure to be relieved.
GENERAL
The cooling system operates under pressure which is controlled
by the pressure relief valve in the radiator cap.
The belt-driven water pump circulates the coolant through the
engine block, cylinder heads, radiator and engine oil cooler. Cir-
culation is controlled by the thermostat which by-passes coolant
flow around the radiator until the engine reaches operating tem-
perature.
Proper cooling is possible only when the system is sealed, the
radiator cap gasket is in good condition, the pressure relief valve
and thermostat are operating properly. The system is free of cool-
ant and air flow restrictions and the system is filled to the proper
level.
Selection and maintenance of the engine coolant is important to
long engine life. The following information provides recommenda-
tions for selecting the engine coolant, maintaining the coolant
inhibitors and servicing the cooling system.
The system operates successfully with a water/antifreeze mixture
or inhibited/conditioned water as the coolant. Water alone allows
rust, scale deposits, and corrosion to occur within the system.
Every 2000 hours, the cooling system should be drained, flushed,
and refilled as described in this section.
When deciding the ratio of antifreeze to water, check the lowest;
temperature in the past, and decide from the mixing rate table
given below.
It is actually better to estimate a temperature about 10°C lower
when deciding the mixing rate.
Mixing rate of water and antifreeze
Min.
atmospheric º C
temperature
Amount of
liters
antifreeze
Amount of
liters
water
190
-5 -10 -15
4.6 6 7.2
15.4 14 12.8
-20 -25 -30
8.2 9.2 9.95
11.8 10.8 10.05
MAINTENANCE.