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5.7.1 COOLANT COMPOSITION
The coolant of the engine is composed and with water, antifreeze liquid and additives in
certain proportion.
LONKING recommends using the mixture of 50% ethylene glycol or propylene
glycol-based antifreeze and 50% soft water as the coolant of the engine in most weather
conditions.
①
Water used in the coolant
The water used in the coolant must be soft water (distilled water is preferable), and
prohibit to use the untreated water as the coolant of the engine. Hard water or the water
containing with calcium and manganese ions with a high rate is apt to produce
water-insoluble compounds and prone to generate furring in the water jacket of t the
engine, causes blocking waterways, heat transfer hindered, and results in engine
overheating; while the water containing higher rate of sulfate or chloride-containing will be
corrosive.
②
Anti-freeze fluid
Antifreeze has the double features of antifreeze and anti-boiling, has anti-corrosion and
other functions as well. Therefore, when the engine is working at a relatively low
temperature, the antifreeze should be used in order to prevent the water freezing in the
cooling system of the engine, to avoid the engine overheating due to the termination of
cooling water circulating, or to keep the body, cylinder cover and heat radiator from
expanding and cracks as the water freezes with the expanded v size. Along with the mass
ratio increasing in the antifreeze coolant, the boiling point of coolant increases, the
freezing point lowers. The antifreeze concentration should not exceed 68.1% (the freezing
point is of -68
℃
), otherwise the performance will be worsened: the freezing point of
coolant will rise instead, and it is easy to form a gel. The normal concentration range is of
40% to 60%, 50% of the concentration of antifreeze cooling fluid is recommended, at the
moment, the freezing point of the coolant is of -35.5
℃
, while the boiling point at
atmospheric pressure is of under 103
℃
, the boiling point in the cooling system is of about
110
℃
.
As antifreeze is flammable, do not close to the naked fire.
③
Additives
Usually the additives contain anti-rust agent, foam suppressing agent, coloring agents etc.
The anti-rust agent can delay or prevent the engine water jacket wall and the radiator from
rusting or corrosion. The air in the coolant will produce a lot of bubbles under the stirring of
the blades of the water pump, these bubbles will hinder the cooling water jacket wall from
heat radiating. The foam suppressing agent can effectively inhibit the generation of the
bubble. Coloring agent normally makes the coolant presenting blue-green or yellow for
Warning
