copyright © 2007 by nelson, a division of thomson canada limited. 12-1chapter 12 cooling system in...

Chapter 12 Copyright © 2007 by Nelson, a division of Thomson Canada Limited. 12-1

Cooling System in Compression Ignition Enginepresentation

NAME SECTION B.N

Sherif mostafa metwaly 3 17

Hosny ahmed Ibrahim 2 33

Esmail abd allah moh. Elshahat 2 16

Mohamed nyazy gamel abd el aziz 5 18

Mohmoud saad moh. seliman 5 30

Mamoud moh. Said eliwa 6 4

Hosam moh. Mahmoud ahmed 2 30


ObjectivesObjectives

• List and describe the major components of the cooling system.

• Describe the operation of the cooling system.• Describe the function of the water pump,

radiator, radiator cap, thermostat, water jackets, block heaters and cooling fans in the cooling system.

• Test and service the cooling system.


Cooling System ComponentsCooling System Components

• Antifreeze/coolant• Thermostat• Water pump• Radiator• Radiator pressure

cap• Expansion tank

• Hoses• Water outlet• Water jackets• Cooling fans• Temperature

indicators• Engine block

heaters

continued…


Cooling System ComponentsCooling System Components


Antifreeze/CoolantAntifreeze/Coolant

• Engine coolant is a mixture of antifreeze and water.

• An ideal mixture in moderate climates is 50% antifreeze and 50% water. This mixture provides a balanced anti-freeze, anti-boil and anti-corrosion protection.

• A recommended mixture in cold climates is 60% antifreeze and 40% water for increased freeze protection.

continued…



• Ethylene glycol based antifreeze is most commonly used and is green in colour.– Ethylene glycol is poisonous and has a sweet

taste that can attract animals and children.

• Propylene glycol based antifreeze has the same basic characteristics of ethylene glycol.– Propylene glycol is not sweet tasting and is less

harmful to animals and children.

continued…



• Safe coolants are also available– Phosphate-free ethylene glycol-based– Phosphate and silicone-free, Organic Acid

Technology (OAT). Orange in colour.– Hybrid Organic Acid Technology (HOAT) with

additives that are not abrasive to water pumps.

• Always use the coolant that is recommended by the manufacturer for each particular engine.


ThermostatThermostat

• The thermostat controls the minimum operating temperature of the engine.

• When the engine is cold, the thermostat prevents coolant flow to the radiator.

• As the engine approaches operating temperature, the thermostat gradually opens allowing coolant flow to the radiator.

continued…


ThermostatThermostat

• Thermostat operation depends on heat acting upon a pellet containing a specially formulated wax and powdered metal.

• Heat causes the wax pellet to expand and force the pellet outward.


Water PumpWater Pump

• The water pump moves coolant through the cooling system.

• Water pumps are centrifugal-type pumps with a rotating paddle-wheel type impeller.

• Water pumps can be belt driven by the crankshaft or camshaft.


RadiatorRadiator

• The radiator transfers heat from the coolant to air passing through it.

• The radiator is a series of tubes and fins that expose the heat from the engine coolant to the most surface area possible, maximizing heat transfer.


Radiator Pressure CapRadiator Pressure Cap

• The cap also contains a vent (vacuum) valve to allow coolant to re-enter the radiator as the system cools and the coolant contracts.

• The pressure cap contains a pressure valve that allows for a pressure increase in the cooling system, which raises the coolants boiling point. The pressure is caused by coolant expansion as the engine warms.


Water JacketsWater Jackets

• Water jackets are hollow passages in the block and cylinder head(s) that surround the areas closest to the cylinders and combustion chambers.


Cooling FansCooling Fans

• Cooling fans provide additional air flow through the radiator at low speed and when the engine is idling.

• The fan may be driven by the engine, via a belt or, or driven by an electric motor.


Engine Block HeatersEngine Block Heaters

• A block heater is a small electric heating element that is installed in a core plug hole and extends into a water jacket.

• This element requires only a short warm-up period to take the deep chill out of an engine block.


Cooling System ServiceCooling System Service

• Pressure test the system for leaks.• Check coolant condition and strength using a

hydrometer or refractometer.• Check radiator cap for proper pressure.• Test thermostat for proper opening and

closing temperatures.

continued…


Cooling System ServiceCooling System Service

• Check hoses for leaks and swelling.• Check the system with a voltmeter for

electrochemical degradation.• Check water pump for bearing failure and

leaks.• Check cooling fans and fan clutch for proper

operation.• Check drive belt tension and condition and

adjust or replace as necessary.


Common Causes of Water Pump Common Causes of Water Pump Bearing FailureBearing Failure

• Improper drive belt tension (both too little or too much tension)

• A bent fan• A missing piece of fan blade• A cracked fan blade• Fan mounting surfaces that are not flush• A worn fan clutch


SummarySummary

• The fluid used as coolant today is a mixture of water and antifreeze coolant.

• V-belts and ribbed belts (called serpentine belts) are used to drive water pumps and power steering pumps, air conditioning compressors, generators, and emission control pumps.

continued…


SummarySummary

• The basic procedure for testing a vehicle’s cooling system includes inspecting components and testing for external and internal leaks.

• Belt problems are easily discovered by visual inspection or by the sound of slippage.

copyright © 2007 by nelson, a division of thomson canada limited. 12-1chapter 12 cooling system in...

Documents