GoodheartWillcox Co Inc Functions 1 Remove Engine Heat

© Goodheart-Willcox Co. , Inc.

Functions 1. Remove Engine Heat § § § Combustion can reach 4500 ºF (2500 ºC) This is hot enough to melt metal parts Cooling system removes excess heat © Goodheart-Willcox Co. , Inc.

2. Maintain Operating Temperature § § 180 ºF to 210 ºF (80 ºC to 100 ºC) When an engine warms to operating temperature, parts expand Ensures that clearances are correct Ensures proper combustion, minimum emissions, and maximum performance © Goodheart-Willcox Co. , Inc.

3. Reach Operating Temperature Quickly § This minimizes several conditions: § § § © Goodheart-Willcox Co. , Inc. poor combustion (poor fuel vaporization) part wear oil contamination reduced fuel economy increased emissions

4. Heater Operation § § Cooling system circulates coolant to the vehicle’s heater Engine heat is used to warm the passenger compartment © Goodheart-Willcox Co. , Inc.

Cooling System © Goodheart-Willcox Co. , Inc.

§ § Water pump forces coolant through engine water jackets Pump is belt or gear driven off the crankshaft © Goodheart-Willcox Co. , Inc.

Cold Engine Operation § § § Thermostat is closed Coolant circulates inside the engine Engine warms quickly © Goodheart-Willcox Co. , Inc.

Hot Engine Operation § § § At operating temperature, thermostat opens Heated coolant then flows through the radiator Excess heat is transferred from the coolant to the air flowing through the radiator © Goodheart-Willcox Co. , Inc.

§ Two common types: § 1. air cooling § 2. liquid cooling © Goodheart-Willcox Co. , Inc.

1. Air Cooling Systems § § Large cylinder cooling fins and outside air remove excess heat Cooling fins increase the surface area of the metal around the cylinder This allows enough heat transfer to the outside air Plastic or metal shrouds duct air over the cylinder fins © Goodheart-Willcox Co. , Inc.

2. Liquid Cooling Systems § § § Circulate coolant through the water jackets Combustion heat is transferred to the coolant Cooling system carries it out of the engine © Goodheart-Willcox Co. , Inc.

Liquid Cooling Advantages § § Precise temperature control Less temperature variation Reduced emissions Improved heater operation © Goodheart-Willcox Co. , Inc.

Air Cooling Versus Liquid Cooling © Goodheart-Willcox Co. , Inc.

Liquid Cooling Heat is transferred to cylinder wall, into coolant and carried away © Goodheart-Willcox Co. , Inc.

Conventional Coolant Flow § § Hot coolant flows from the cylinder head to the radiator After being cooled in the radiator, the coolant flows back into the engine block © Goodheart-Willcox Co. , Inc.

Reverse Flow Cooling § § § Cool coolant enters the head and hot coolant exits the block to return to the radiator Helps keep a more uniform temperature throughout the engine Found on high-performance engines © Goodheart-Willcox Co. , Inc.

§ Components: § § § © Goodheart-Willcox Co. , Inc. water pump radiator hoses radiator fan thermostat

Water Pump A ribbed belt powers this pump Crank pulley Impeller Ribbed belt Water pump pulley © Goodheart-Willcox Co. , Inc.

Impeller Pump Coolant is thrown outward by centrifugal force, producing suction in the center of the pump housing © Goodheart-Willcox Co. , Inc.

Coolant Flow © Goodheart-Willcox Co. , Inc.

Coolant Flow (Conventional) § § Coolant flows out of the radiator, through the lower hose, into the engine It then flows through the pump, around the cylinders, through the heads, up through thermostat, and back into the radiator © Goodheart-Willcox Co. , Inc.

Hoses § Radiator hoses § carry coolant between the engine water jackets and the radiator § lower hose is exposed to water pump suction so a spring may prevent collapse § Heater hoses § carry hot coolant to the heater core § smaller diameter than radiator hoses © Goodheart-Willcox Co. , Inc.

Radiator and Heater Hoses © Goodheart-Willcox Co. , Inc.

Radiator Hoses Two basic types of radiator hoses © Goodheart-Willcox Co. , Inc.

Hose Clamps Three basic types of hose clamps © Goodheart-Willcox Co. , Inc.

Radiator Transfers coolant heat to the outside air © Goodheart-Willcox Co. , Inc.

Radiator Types Downflow © Goodheart-Willcox Co. , Inc. Crossflow

Radiator Cap § § Seals the radiator Pressurizes the system Relieves excess pressure Allows coolant flow between the radiator and the coolant reservoir © Goodheart-Willcox Co. , Inc.

Radiator Cap © Goodheart-Willcox Co. , Inc.

Radiator Cap Pressure Valve § § Spring-loaded disk Normally, water boils at 212 ºF (100 ºC) For each pound of pressure increase, boiling point goes up about 3 ºF (1. 6 ºC) Typical pressure: § 12– 16 psi § raises boiling point to 250– 260 ºF (121– 127 ºC) © Goodheart-Willcox Co. , Inc.

Radiator Cap Vacuum Valve Opens to allow flow back into the radiator when the coolant temperature drops © Goodheart-Willcox Co. , Inc.

§ Closed cooling system § uses an expansion tank § overflow tube is routed into reservoir tank § Open cooling system § allows excess coolant to leak onto the ground © Goodheart-Willcox Co. , Inc.

Pressure Cap Operation Hot engine © Goodheart-Willcox Co. , Inc.

Pressure Cap Operation Cold engine © Goodheart-Willcox Co. , Inc.

Cooling System Fans § § § Pull air through the core of the radiator Increase volume of air through the radiator Driven by fan belt or electric motor © Goodheart-Willcox Co. , Inc.

Radiator Shroud Ensures that the fan pulls air through the radiator core © Goodheart-Willcox Co. , Inc.

Thermostat § § § © Goodheart-Willcox Co. , Inc. Senses coolant temperature and controls coolant flow through the radiator Reduces coolant flow on cold engine Increases coolant flow on hot engine

Thermostat A temperature-sensitive valve © Goodheart-Willcox Co. , Inc.

Thermostat Operation § Cold engine § wax-filled pellet has contracted § spring holds valve closed § Hot engine § when heated, pellet expands § spring tension is overcome § valve opens © Goodheart-Willcox Co. , Inc.

Thermostat Operation A. Cold engine B. Hot engine © Goodheart-Willcox Co. , Inc.

Thermostat Operation Cold engine © Goodheart-Willcox Co. , Inc.

Thermostat Operation Hot engine © Goodheart-Willcox Co. , Inc.

Bypass Valve Permits circulation through the engine when thermostat is closed © Goodheart-Willcox Co. , Inc.

§ § § Composed of ethylene glycol mixed with water Prevents winter freeze-up Prevents rust and corrosion Lubricates the water pump Cools the engine © Goodheart-Willcox Co. , Inc.

Corrosion Protected with antifreeze © Goodheart-Willcox Co. , Inc. Water only

Antifreeze/Water Mixture Lowers coolant freezing point to about -34 ºF (-37 ºC) © Goodheart-Willcox Co. , Inc.