Cooling
System
PURPOSE
OF
COOLING SYSTEM
Purpose of the cooling system is to carry heat away
from hot engine components in order to maintain
proper running conditions and clearances. Overheat-
ing can severely damage engines. The cooling sys-
tem must carry off the excess heat.
Regulating coolant temperature helps keep the engine
at the optimal heat level for each operating condition.
After starting, the engine must warm up quickly. Dur-
ing periods of peak output, it must be adequately
cooled.
ANTI-FREEZE AND CORROSION
Corrosion can shorten an engine's life by plugging up
radiator cores, building up around hot spots near the
exhaust valves, and settling in low areas of the block.
The corrosive sediment insulates against proper heat
transfer and holds heat in. Most of the metals used in
cooling systems are susceptible to corrosion damage
that causes coolant leaks and the temperature to rise
above safe, normal limits.
To prevent corrosion, a mixture of anti-freeze and
water should always be used as an engine coolant,
even when freezing temperatures are not expected.
Besides preventing coolant freeze up, anti-freeze
contains rust inhibitors that prevent corrosion. Most
an ti-f reeze manufacturers recommend a mini mum
50-50
mix of ethylene glycol anti-freeze and water for
winter and summer in closed water systems with a
complete change every year to avoid corrosion and
more expensive damage.
HIGH TEMPERATURE CUT-OFF SWITCH
The high temperature cut-off switch shuts down the
engine if the coolant reaches a dangerously high
temperature. This normally closed switch senses
coolant temperature in the engine cooling jacket.
When engine temperature rises beyond a specific
point the switch opens, breaking the circuit to the fuel
solenoid. When coolant temperature falls to a safe
operating range the switch closes, permitting engine
restarting.
Stopping of the engine due to action of the high
temperature cut-off switch is not a normal condition.
Examine the cooling system to determine the cause
of the overheating and repair as required.
16
COOLING SYSTEM MAINTENANCE
The cooling system including the block and radiator
should be cleaned and flushed at least once a year.
This
is
especially true in cold weather conditions or
when preparing unit for extended storage (over
30
days or more)!
The cooling system can work efficiently only when it
is clean. Scale and rust in the cooling system slow
down heat absorption and restrict water flow.
The thermostat is calibrated to open at 150°F
*
2OF.
It
should be checked also.
I
An appropriate anti-freeze mixture should be used in
colder climates as necessary.
Check the fan belt tension periodically. For proper
operation of the water pump, the fan belt should be
tight enough to prevent slipping.
Check the water pump for wear periodically. Loosen
the fan belt and move the fan and water pump pulley
back and forth. If wear is excessive, replace the
bearing.
Cleaning and Flushing Cooling System
To clean rust and scale deposits from the cooling
system, drain system and then fill with clean water
and cleaning solution. Use an approved chemical
cleaner (such as type used for cleaning automotive
cooling systems) and follow instructions provided by
the supplier.
Contact with hot coolant might
result in serious burns. Do not bleed
hot, pressurized coolant from a closed cooling
system.
Cleaning solutions typically contain
strong chemicals that can cause
burns or other injury if used improperly. Read all
warning labels carefully before using.
When cleaning is complete, drain cleaning solution
and flush system. For best results engine and radia-
tor, or heat exchanger, should be reverse flushed.
Allow engine to cool as much as possible before
flushing with cold water.
Never pour cold wafer into a hot
engine. Doing
so
may crack the
head or the cylinder block. Do not operate engine
without coolant for even a few minutes.
Flush system if engine operation indicates clogged
passages or overheating.
Redistribution or publication of this document,
by any means, is strictly prohibited.
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