Transcript Engine Overheating

Engine Overheating
How hot is too hot ?
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Most engines today are designed to operate
within a "normal" temperature range of about
195 to 220 degrees F (91.28 to 105.28 degrees c) .
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A relatively constant operating temperature is
absolutely essential for proper emissions control,
good fuel economy and performance.
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Engine overheating can be caused by a
combination of two factors: too much heat or not
enough cooling.
Causes Of Engine Overheating
1) A defective thermostat
A defective thermostat
The thermostat is a valve located in the cooling
system of an engine, which is closed when the
engine coolant is cold and opens gradually in
response to the engine heating and thereby
controlling the temperature of the coolant and
rate of coolant flow through the engine block.
2) A defective electric cooling fan or
fan clutch
A defective electric cooling fan or fan clutch
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The fan clutch is a coupling device that is located
between the water pump shaft and the fan.
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The fan clutch is designed to improve the vehicle’s
cooling system efficiency while reducing the load
on the engine and loss of energy caused by the fan
itself.
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The Fan Clutch allows the fan to operate at lower
speeds and effectively detach at higher speeds
when the vehicle is moving and air movement due
to velocity aids to cool the engine.
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Fan Clutch is wearing out or has failed to do its
job then if the fan speed does not increase when
engine is running hot or if the fan speed does not
increase until engine is excessively hot.
3) A collapsed radiator hose
A collapsed radiator hose
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The radiator hoses should be in good shape,
not cracked, brittle or leaking.
Other than obvious damage, hoses can
restrict coolant flow.
4) An eroded or loose water
pump impeller
An eroded or loose water pump impeller
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A typical sign of a failing water pump is bad is
typically a leak. A leak is typically occurring
through the seal and bearing.
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Sometimes the water pump impeller can loosen up
on the pump shaft and not turn, although the
water pump pulley appears to be turning
normally. If the impeller does not spin, there will
be little or no circulation of coolant through the
engine.
5) A defective radiator cap
The cooling system of an engine is designed as a
sealed system with the engine coolant held under
pressure. When under pressure, water and
engine coolant boil at a higher temperature. As
your coolant and water increase in temperature
and approach the boiling point, the state of the
liquid begins to change to a gas, seen as steam.
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A gas is much less efficient in cooling your engine
than a liquid. So increasing the pressure increases
the boiling point, allowing the coolant and water to
do a much better job at removing heat.
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A functioning radiator cap will maintain its rated
pressure.
A 50/50 mixture of water and ethylene glycol
will boil at 225 degrees in the cooling system
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6) Fan belts fail
Fan belts fail
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Most cars on the road use a serpentine belt. A
serpentine belt is a single belt that drives all the
engine accessories. If a serpentine belt fails, all
engine accessories will stop turning. That includes
power steering, air conditioning compressor,
alternator, and of course the water pump.
7) Damaged Fan Shroud
Damaged Fan Shroud
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The fan shroud directs the air from the fan, directly
into the radiator making the fan efficient. A missing
or damaged fan shroud will direct air from the fan
directly through the radiator. . If there is not enough
air is moving through the radiator to sufficiently cool
the fluid, the result is an overheated engine.
8) Dirty engine
Dirty engine
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Dirt on an engine can act as an insulator, much
like a blanket which keeps the temperature in
the engine, rising its temperature.
10) Head gasket
Head gasket
A head gasket is a gasket that sits between the
engine block and cylinder head in an internal
combustion engine. Its purpose is to seal the
cylinders to ensure maximum compression and
avoid leakage of coolant or engine oil into the
cylinders.
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Overheating problems due to the head gasket
may also be due to a break in the head gasket
that is allowing combustion gasses to be
pushed into the coolant , the result could be
trapped air in the water pump.
11) FRICTION
Too much friction , oil and some additives aid
to reduce friction.
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Team Work
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B.N
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1) Magdy Saaid Mohammed Ali.
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4
14
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2) Mohammed Shehata Mohammed.
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4
29
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3) Mohammed Abd el aal Saad.
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5
1
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4) Mohammed Mansour Mostafa.
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5
14
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5) Mohammed Wafaey Mohammed Ali.
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5
20
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6) Haytham Atef El saied Ahmed.
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6
25