Doosan G20P-5, Service Manual, Page: 22 / 306

G424F(FE) Service Manual Chapter 2. Recommended Maintenance 20
Cooling System Maintenance
Coolant Recommendation
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.
CAUTION
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.
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
Antifreeze
DOOSAN recommends selecting automotive
antifreeze suitable for gasoline engines using
aluminum alloy parts. The antifreeze should meet
ASTM-D3306 standard.
Check Coolant Level
•
The items below are a general guideline for
system checks. Refer to the engine
manufacturer’s specific recommendations for
proper procedures.
•
Engine must be off and cold.
WARNING—PROPER USE
Never remove the pressure cap on a hot engine.
•
The coolant level should be equal to the “COLD”
mark on the coolant recovery tank.
•
Add approve coolant to the specified level if the
system is low.
Inspect Coolant Hoses
•
Visually inspect coolant hoses and clamps.
Remember to check the two coolant lines that
connect to the pressure regulator/converter.
•
Replace any hose that shows signs of leakage,
swelling, cracking, abrasion or deterioration.