CAT Engine-Cooling System

TO EXTEND THE ENGINE LIFE

Use good quality cooling Water 

Prevent overheating & overcooling

Change the cooling water periodically & flush the system

Use the appropriate antifreeze & additives

Periodically clean & inspect the radiator, engine area, & cooling system

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CAT DIESEL ENGINES systems components

Primary purpose of a cooling system • an engine’s cooling system is responsible for maintaining adequate engine temperatures.

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CAT DIESEL ENGINES systems components

Basic operating principle of a cooling system • The cooling system circulates coolant through the engine to remove the heat created by combustion 7 friction. It uses the principle of heat transfer.

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• Heat transfer  • Heat always moves from a hot “source”to a cooler  “target”. Source & target could be metal, fluid or air. The key is the difference in relative temperature between the two.The greater the difference,the more heat will transfer.

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CAT DIESEL ENGINES systems components

Cooling systems: - radiator - keel cooler - shunt cooling - heat exchanger cooling

Basic components: - radiator - fan - coolant - water pump - engine oil cooler - water temperature regulator - pressure cap

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CAT DIESEL ENGINES Coolant flow

Water pump oil cooler  cylinder block  cylinder head  (regulator) radiator  water pump.

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 Engine Power Dissipation 30% Exhaust HP

7% Radiated HP 30% Cooling HP 33% Flywheel HP

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Cooling System Functions • Remove Heat Generated from Fuel Combustion  –  Burn Temperatures Can Reach 3,500°F (1927°C)

• Transfer Heat From:  –  Transmission Oil Coolers  –  Hydraulic Oil Coolers  –  Water Cooled Exhaust Manifolds  –  Water Cooled Turbocharger Shields/Housings  –  Torque Converter/Retarder Coolers  –  Jacket Water After Coolers

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Cooling System Components • Radiator  • Fan • Coolant • Water Pump • Engine Oil Cooler  • Water Temperature Regulator 

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Cooling system temperature • Cooling systems are designed to keep an engine operating within a desired temperature range. • Temperature of the coolant must remain high to allow the engine to operate efficiently.however, temperature must stay low enough to prevent the coolant from boiling. • A cooling system regulates temperature by transferring heat from the engine to the coolant &eventually, into the air.

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CAT DIESEL ENGINE   pressure cap

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CAT DIESEL ENGINE   pressure cap

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Cooling system temperature • A major factor of heat transfer is the difference between the temperature of coolant inside the radiator & the temperature of surrounding air. • When the difference coolant temperature & the ambient temperature increases, the rate of heat transfer increases.

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Cooling system temperature • The temperature at which coolant boils depends on the three factors.  –  Pressure at which cooling system operates.  –  Altitude at which cooling system operates  –  Amount & type of antifreeze in coolant mixture.

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CAT DIESEL ENGINE   Altitude compensation

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Cooling System Maintenance • 60% of Premature Engine Failures Can Be Attributed to Cooling System Problems

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Coolant  • Function  –  Transfer Heat from Hot Engine Components to a Radiator or Heat Exchanger 

• Characteristics  –  High Boiling Temperature  –  Freeze Protection  –  Corrosion Resistance  –  Scale and Deposit Prevention  –   Non Foaming  –  Minimum Sediment

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 Heat Transfer  • Water Is the Most Efficient Heat Transfer Agent  –  Drawbacks: • Contains Chlorides, Sulfates, and Suspended Solids • Causes Scales, Deposits • Leads to Clogged Radiators and Failed Water Pumps • Builds Sediment

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 Heat Transfer  • Water Is the Most Efficient Heat Transfer Agent  –  Drawbacks: • Improper pH Level • Attacks Copper, Aluminum and Steel Engine Components • Causes Corrosion • Damages Seals • Lower Boiling Point • Lower Performance

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Water Quality • Must Conform to Established Levels of:  –  Chloride

2.4 gr/gal max

 –  Sulfates

5.9 gr/gal max

 –  Total Hardness

10 gr/gal max

 –  Total Solids

20 gr/gal max

 –   pH Level

5.5 - 9.0

• Caterpillar Recommends Distilled or De-ionized Water  •  Never Use Water Alone as a Coolant

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CAT DIESEL ENGINE 

• Overheating,overcooling,pitting,cavitation, erosion,cracked heads, piston seizures,&  plugged radiators are classic cooling system failures.

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