Komatsu PC12R-8, Operation & Maintenance Manual

Page: 143 / 208

MAINTENANCE PLAN
141
4.7.1 WHEN REQUIRED
4.7.1.a WASHING THE COOLING CIRCUIT
DANGER
•
Be extremely careful when carrying out this maintenance operation, since the engine must be running;
one operator must remain on the machine and the operators must decide the words and signals to be
used in advance.
•
As soon as the machine has been stopped the coolant is very hot and under pressure and may cause
serious burns; let the engine cool down until it reaches approximately 40÷45°C before starting the
washing operations.
•
Slowly loosen the radiator cap, to release the residual pressure.
•
Let all the work equipment safety locks engaged.
•
Oils, filters, the coolant and the battery are considered special waste and must be collected and dis-
posed of according to the anti-pollution regulations in force.
Whenever passing from the use of water to the use of antifreeze
fluids and vice versa, it is necessary to wash the circuit in order
to eliminate either the oxide deposits and the limestone encrus-
tations. Proceed as follows:
1 - Open the engine hood (See “3.5.1 ENGINE HOOD”).
2 - With the fluid still warm, open the drain cock (2) of the radi-
ator, remove the drain plug (3) positioned on the engine
block and the radiator cap (1).
Use a 17 mm hexagon spanner.
3 - Let all the fluid flow out, put back the plug (3) on the engine
block and close the radiator drain cock (2).
4 - Introduce a high-quality scale remover in the radiator, in the
doses indicated on the package (remember that the capaci-
ty of the cooling system is approximately 3.6 litres) and fill
the radiator with water.
5 - Start the engine and let it run at high rpm for about 15 min-
utes.
6 - Lower the engine speed to idling and drain the scale remov-
er through the cock (2) of the radiator, at the same time fill-
ing the radiator with running water for at least 40 minutes.
7 - Stop the engine, let all the water flow out, close the radiator
cock (2) and fill the circuit definitively with water or coolant.
8 - Start the engine and after a few minutes check the fluid lev-
el in the radiator; if necessary, top up before tightening the
cap (1).
9 - After draining the water from the tank (4), wash the inside of
the tank and fill it with water or coolant until reaching a level
included between the MIN. and MAX. marks.
10 - Close the engine hood.
IMPORTANT
☞
•
The circuit must be washed more frequently if the water
used contains a high quantity of calcium salts, that is, if
the water is very hard.
RWA06350
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