Clean Inside Of Cooling System - Komatsu PC450-8 Operation & Maintenance Manual

MAINTENANCE

CLEAN INSIDE OF COOLING SYSTEM

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Immediately after the engine is stopped, the coolant is at a high temperature and the radiator is under
high internal pressure.
If the cap is removed to drain the coolant in this condition, there is a hazard of burns. Wait for the tem-
perature to go down, then
turn the cap slowly to release the pressure before removing it.
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When starting the engine while cleaning the machine, set the lock lever in the lock position to prevent
the machine from moving.
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For details of starting the engine, see "BEFORE STARTING ENGINE (3-111)" and "STARTING ENGINE
(3-128)" in the OPERATION section.
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There is danger of touching the fan if the undercover is left removed.
Never enter behind the machine when the engine is running.
Stop the machine on level ground when cleaning or changing the coolant.
Clean the inside of the cooling system, change the coolant and replace the corrosion resistor according to the
table below.
Antifreeze coolant
Komatsu supercoolant
(AF-NAC)
Permanent type antifreeze
(All-season type, *)
*: Permanent type antifreeze shall meet the requirements of ASTM D3306-03.
The coolant has the important function of preventing corrosion as well as preventing freezing.
Even in the areas where freezing is not an issue, the use of antifreeze coolant is essential.
Komatsu machines are supplied with Komatsu Supercoolant (AF-NAC). Komatsu Supercoolant (AF-NAC) has
excellent anticorrosion, antifreeze and cooling properties and can be used continuously for 2 years or 4000
hours.
Komatsu Supercoolant (AF-NAC) is strongly recommended wherever available.
When using Komatsu Supercoolant (AF-NAC), there is no need to use a corrosion resistor.
When no corrosion resistor is used, use the special cover (600-411-9000). Please consult your Komatsu distrib-
utor about the method of installing.
To maintain the anticorrosion properties of Supercoolant (AF-NAC), always keep the density of Supercoolant
between 30% and 68%.
When deciding the ratio of antifreeze to water, check the lowest temperature in the past, and decide from the
mixing table given below.
It is actually better to estimate and temperature about 10°C lower when deciding the mixing ratio.
The mixing ratio depends on the ambient temperature, but it should always be a minimum of 30% by volume
(antifreeze/total amount of coolant x 100).
The freezing temperature of undiluted antifreeze is -15°C. Do not store undiluted antifreeze at a temperature of
below -15°C.
WARNING
Interval of cleaning inside of cooling system
and changing antifreeze coolant
Every two years or every 4000 hours which-
ever comes first
Every year (autumn) or every 2000 hours
whichever comes first
MAINTENANCE PROCEDURE
Replacing corrosion resistor
unnecessary
Every 1000 hours
and when cleaning the inside
of the cooling system
and when changing coolant
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