School

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School

• Teacher

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COOLING SYSTEMS
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WHAT IS THE PURPOSE OF COOLING SYSTEM?

• KEEP ENGINE AT MOST EFFICIENT OPPERATING
  TEMPERATURE

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• WHERE DOES THE HEAT COME FROM?

BURNING FUEL
HOW DOES THE ENGINE USE THIS ENERGY?
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35 LOST OUT EXHAUST
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35 LOST TO COOLING SYSTEM
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15 LOST TO FRICTIONAL LOSSES
LOST TO COOLING 35
LOST TO EXHAUST 35
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APPROXIMATELY 15 LEFT TO MOVE THE CAR.
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LOST TO EXHAUST 35
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CYLINDER WALL TEMPERATURE MUST BE KEPT BELOW 500
DEGREES F.WHY?

• OIL BREAKS DOWN (BURNS)

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THREE TYPES OF HEAT TRANSFER

• CONDUCTION
• CONVECTION
• RADIATION

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CONDUCTION

• TRANSFER OF HEAT THRU SOLIDS

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CONVECTION

• TRANSFER OF HEAT THRU LIQUIDS OR VAPORS

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RADIATION

• TRANSFER OF HEAT THRU LIGHT RAYS

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HERE ARE THE COMPONENTS OF THE LIQUID COOLING
SYSTEM.
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FOUR PURPOSES OF USING ANTIFREEZE
1. LOWER FREEZING POINT OF WATER
2. RAISE BOILING POINT OF WATER
3. PREVENT RUST/CORROSION AND DEPOSITS
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FOUR PURPOSES OF USING ANTIFREEZE
PURE WATER 32F
25 ANTIFREEZE 10F
PURE ANTIFREEZE -10F
50 ANTIFREEZE -34F
68 ANTIFREEZE -92F
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FOUR PURPOSES OF USING ANTIFREEZE

• 1. LOWER FREEZING POINT OF WATER

2. RAISE BOILING POINT OF WATER
PURE ANTIFREEZE BOILS AT 320F
50 ANTIFREEZE BOILS AT 225F
25 ANTIFREEZE BOILS AT 218F
WATER BOILS AT 212F
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RUST/CORROSION AND DEPOSIT SLOW DOWN THE HEAT
TRANSFER
ACTS AS A BLANKET
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THERE ARE DIFFERENT KINDS OF COOLANT

• GREEN (CONVENTIONAL)
• RECOMMENDED TO BE CHANGED ONCE A YEAR
• PINK (DEX COOL)
• RECOMMENDED TO BE CHANGED EVERY 5 YEARS

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WATER PUMP

• CAUSES COOLANT TO FLOW
• USUALLY DRIVEN BY BELT FROM CRANK
• SHAFT SUPPORTED BY BEARNING
• SEAL PREVENTS COOLANT LEAKAGE

WEEP HOLE TO KEEP LEAKING COOLANT AWAY FROM
BEARING
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RADIATORS
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PRESSURE CAPS
SEALS COOLING SYSTEM TO ALLOW PRESSURE TO FORM
FROM EXPANDING COOLANT
PRESSURE RAISES BOILING POINT OF WATER 1 LB OF
PRESSURE RAISES BOILING POINT 3 DEGRES F
PREVENTS A VACUUM FROM FORMING AS COOLANT COOLS
AFTER SHUT DOWN
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PRESSURE CAP OPERATION
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WARNING! WARNING! WARNING!
NEVER REMOVE CAP FROM HOT RADIATOR
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THERMOSTAT OPERATION
NOTE! WATER PUMP CIRCULATES ANYTIME ENGINE IS
RUNNING
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ENGINE UP TO TEMPERATURE
WAX PELLET EXPANDS PUSHING VALVE OPEN.
VALVE OPEN, COOLANT CAN FLOW TO RADIATOR TO COOL.
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THERMOSTAT NOTES

• CLOSED COOLANT TRAPED IN ENGINE, GETS HOT
• OPEN COOLANT CAN FLOW TO RADIATOR TO COOL
• ALLOWS JUST THE RIGHT AMOUNT TO FLOW TO KEEP EVEN
  TEMPERATURE
• MOST MODERN VEHICLES CALL FOR 195 F.

• STUCK CLOSED
• ENGINE OVERHEATS
• STUCK OPEN
• MORE EMISSIONS
• HEATER BLOWING COLD AIR

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SOFT PLUGS

• ALSO CALLED
• FREEZE PLUGS
• EXPANSION PLUGS
• SAND PLUGS
• CORE PLUGS

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HOSES

• TYPES
• PRE-FORMED
• FLEX
• SPRINGS
• WHEN TO CHANGE
• HARD
• SOFT
• BULGING
• BEFORE THEY BREAK
• RECOMMENDED EVERY 6 YEARS

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FANS

• PURPOSE
• PROVIDE AIR FLOW THRU RADIATOR AT LOW SPEEDS.
  NOT NEEDED AT HIGH SPEEDS
• TYPES
• SOLID
• ENERGY CONSERVING
• FLEX
• CLUTCH
• ELECTRIC