G643 (E) Service Manual Chapter 3. Engine Mechanical System
55
NOTE
: Another condition that can cause heat
problems is the ignition timing. Retarded (late)
timing causes the engine to send more heat to the
cooling system. Advanced (early) timing causes the
engine to send less heat to the cooling system.
Cooling System Recommendation
Coolant Information
The engine cooling system is provided with a
mixture of 50% ethylene glycol anti-freeze and 50%
water (For the vehicles of tropical area, the engine
cooling system is provided with a mixture of 40%
ethylene glycol anti-freeze and 60% water at the
time of manufacture.)
Since the cylinder head and water pump body are
made of aluminum alloy casting, be sure to use a 30
to 60% ethylene glycol antifreeze coolant to assure
corrosion protection and freezing prevention.
WARNING
If the concentration of the antifreeze is below
30%, the anticorrosion property will be adversely
affected. In addition, if the concentration is
above 60%, both the antifreeze and engine
cooling properties will decrease, adversely
affecting the engine. For these reasons, be sure
to maintain the concentration level within the
specified range.
To prevent damage to your engine, never add
coolant to an overheated engine. Allow the engine to
cool first.
If the lift truck is to be stored in, or shipped to, an
area with freezing temperatures, the cooling system
must be protected to the lowest expected outside
(ambient) temperature.
The engine cooling system is protected with a
commercially available automotive antifreeze, when
shipped from the factory.
Check the specific gravity of the coolant solution
frequently in cold weather to ensure adequate
protection.
Clean the cooling system if it is contaminated, if the
engine overheats or if foaming is observed in the
radiator.
Old coolant should be drained, system cleaned and
new coolant added as recommended with the
commercially available automotive antifreeze.
Filling at over 20 liters per minute can cause air
pockets in the cooling system.
After draining and refilling the cooling system,
operate the engine with the radiator cap removed
until the coolant reaches normal operatin
temperature and the coolant level stabilizes. Add
coolant as necessary to fill the system to the proper
level.
Operate with a thermostat in the cooling system all
year-round. Cooling system problems can arise
without a thermostat.
Coolant Water
Hard water, or water with high levels of calcium and
magnesium ions, encourages the formation of
insoluble chemical compounds by combining with
cooling system additives such as silicates and
phosphates.
The tendency of silicates and phosphates to
precipitate out-of-solution increases with increasing
water hardness. Hard water, or water with high
levels of calcium and magnesium ions encourages
the formation of insoluble chemicals, especially after
a number of heating and cooling cycles.
DOOSAN prefers the use of distilled water or
deionized water to reduce the potential and severity
of chemical insolubility.
Acceptable Water
Water Content
Limits (ppm)
Chlorides (CI)
40 maximum
Sulfates (SO4)
50 maximum
Total Hardness
80mg/
ℓ
maximum
Total Solids
250 maximum
pH
6.0 ~ 8.0
ppm = parts per million
Using water that meets the minimum acceptable
water requirement may not prevent drop-out of
these chemical compounds totally, but should
minimize the rate to acceptable levels.
Antifreeze
DOOSAN recommends selecting automotive
antifreeze suitable for gasoline engines using
aluminum alloy parts. The antifreeze should meet
ASTM-D3306 standard.
