Copyright © 2007 by Nelson, a division of Thomson Canada Limited. 12-1Chapter 12 Cooling System in Compression Ignition Engine presentation B.NSECTION NAME 17 3Sherif mostafa metwaly 332 Hosny ahmed Ibrahim 162 Esmail abd allah moh. Elshahat 185 Mohamed nyazy gamel abd el aziz 305 Mohmoud saad moh. seliman 46 Mamoud moh. Said eliwa 302 Hosam moh. Mahmoud ahmed

Copyright © 2007 by Nelson, a division of Thomson Canada Limited. 12-2Chapter 12 Objectives 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.

Copyright © 2007 by Nelson, a division of Thomson Canada Limited. 12-3Chapter 12 Cooling 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…

Copyright © 2007 by Nelson, a division of Thomson Canada Limited. 12-4Chapter 12 Cooling System Components

Copyright © 2007 by Nelson, a division of Thomson Canada Limited. 12-5Chapter 12 Antifreeze/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…

Copyright © 2007 by Nelson, a division of Thomson Canada Limited. 12-6Chapter 12 Antifreeze/Coolant 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…

Copyright © 2007 by Nelson, a division of Thomson Canada Limited. 12-7Chapter 12 Antifreeze/Coolant 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.

Copyright © 2007 by Nelson, a division of Thomson Canada Limited. 12-8Chapter 12 Thermostat 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…

Copyright © 2007 by Nelson, a division of Thomson Canada Limited. 12-9Chapter 12 Thermostat 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.

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

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

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

Copyright © 2007 by Nelson, a division of Thomson Canada Limited Chapter 12 Water Jackets Water jackets are hollow passages in the block and cylinder head(s) that surround the areas closest to the cylinders and combustion chambers.

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

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

Copyright © 2007 by Nelson, a division of Thomson Canada Limited Chapter 12 Cooling 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…

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

Copyright © 2007 by Nelson, a division of Thomson Canada Limited Chapter 12 Common Causes of Water Pump Bearing 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

Copyright © 2007 by Nelson, a division of Thomson Canada Limited Chapter 12 Summary 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…

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