Service manual

G420F(FE) Service Manual Chapter 3. Engine Mechanical System 58
Cooling System Heat Problems
To check if there is a good reason for heat problems
do the checks that follow:
1. The indications of a heat problem are as follows:
a. High coolant temperature indicator light is on or
needle of coolant temperature gauge is in red
range.
b. Coolant boils out (comes out because of too
much heat) of the cooling system during
operations.
c. Coolant boils out on the floor when the engine is
stopped.
d. Coolant must be added at the end of each shift
but Steps b and c are not present.
2. If indication in Step 1 a is only present. It is
possible the problem is only a damaged gauge,
light or sender. Make a replacement of the
defective part.
3. If indication in Step 1b is present, do the
procedure that follows:
a. Run the engine at medium idle (1200 rpm) for
three minutes after high idle operation. This cools
off the hottest parts of the engine before it is
stopped.
b. Install a coolant recovery system on the truck, if
not already equipped.
4. If indications in Step 1b, 1c or 1d are present, but
Step 1a is not and the high temperature indicator
light does work, the problem can be a damaged
radiator cap seal or there can be a leak in the
cooling system. Complete the procedure that
follows:
a. Do the Pressure Cap Test, Cooling System Leak
Check, Thermostat Test and Belt Adjustment in
the Testing And Adjusting.
b. Clean the radiator with hot water (steam clean) at
low pressure and use detergent or air according
to the different types of debris that caused the
radiator to be dirty (plugged).
c. Check the engine high idle setting.
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.