Testing And Adjusting; Cooling System Visual Inspection; Cooling System Tests - Daewoo G424 Gasoline Service Manual

Testing & Adjusting
Adhere to the following warnings when performing any
tests or adjustments while the engine is running:
Work carefully around an engine that is running.
Engine parts that are hot, or parts that are moving,
can cause personal injury.
Exhaust fumes contain carbon monoxide (CO)
which can cause personal injury or death. Start and
operate the engine in a well ventilated area only. In an
enclosed area, vent the exhaust to the outside.
This engine has a pressure type cooling system. A
pressure type cooling system gives two advantages.
The first advantage is that the cooling system can
have safe operation at a temperature that is higher
than the normal boiling (steam) point of water. The
second advantage is that this type system prevents
cavitation (the sudden making of low pressure bubbles
in liquids by mechanical forces ) in the water pump.
With this type system, it is more difficult for an air or
steam pocket to be made in the cooling system.
The cause for an engine getting too hot is generally
because regular inspections of the cooling system
were not made. Make a visual inspection of the
cooling system before testing with testing equipment.

Cooling System Visual Inspection

Do not loosen the filler cap or pressure cap on a hot
engine. Steam or hot coolant can cause severe burns.
1. After the engine is cool, loosen the filler cap (on a
radiator with a pressure cap, turn it to the first stop)
to let pressure out of the cooling system. Then
remove filler or pressure cap.
2. Check coolant level in the cooling system.
3. Look for leaks in the system.
G424 Service Manual
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4. Look for bent radiator fins. Be sure that air flow
through the radiator does not have a restriction.
5. Inspect the drive belts for the fan.
6. Check for damage to the fan blades.
7. Look for air or combustion gas in the cooling system.
8. Inspect the filler cap and the surface that seals the
cap. This surface must be clean.
9. Look for a large amount of dirt in the radiator core
and on the engine.
10. Check for loose or missing fan shrouds that cause
poor flow of cooling air.

Cooling System Tests

IDES108S
Remember that temperature and pressure work
together. When making a diagnosis of a cooling
system problem, temperature and pressure must both
be checked. Cooling system pressure will have an
effect on cooling system temperatures. For an
example, look at the chart to see the effect of
pressure and height above sea level on the boiling
(steam) point of water.
111 Cooling System