Daewoo G424 Gasoline, Service Manual

Page: 116 / 199

G424 Service Manual Cooling System 115
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.
DAEWOO prefers the use of distilled water or
deionized water to reduce the potential and severity of
chemical insolubility.
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
NOTICE
DAEWOO recommends that the coolant mix contain
50% commercially available automotive antifreeze, or
equivalent, and acceptable water to maintain an
adequate water pump cavitation temperature for efficient
water pump performance.
Premix coolant solution to provide protection to the
lowest expected outside (ambient) temperature. Pure
undiluted antifreeze will freeze at -23°C (-10°F).
Only use a greater concentration (above 50%) of
commercially available automotive antifreeze an needed
for anticipated outside (ambient) temperatures. Do not
exceed the recommendations, provided with the
commercially available automotive antifreeze, regarding
the coolant mixture of antifreeze to water.
DAEWOO recommends selecting automotive
antifreeze suitable for gasoline engines using
aluminum alloy parts. The antifreeze should meet
ASTM-D3306 standard.
Make proper antifreeze additions.
Adding pure antifreeze as a makeup solution for
cooling system top-up is an unacceptable practice. It
increases the concentration of antifreeze in the
cooling system which increases the concentration of
dissolved solids and undissolved chemical inhibitors in
the cooling system. Add antifreeze mixed with water to
the same freeze protection as your cooling system.
Acceptable Water
Water Content Limits (ppm)
Chlorides (Cl) 40 maximum
Sulfates (SO
4
) 50 maximum
Total Hardness 80mg/
MM
maximum
Total Solids 250 maximum
pH 6.0~8.0