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Cooling System Functions

Cooling System Functions. Cooling System. Two types Air Cooled Liquid Cooled. Air Cooled Engines. Advantage Low production cost Disadvantage Vehicle motion is required to keep cool. Air cooled Engines. Finned cylinders Why

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Cooling System Functions

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  1. Cooling System Functions

  2. Cooling System • Two types • Air Cooled • Liquid Cooled

  3. Air Cooled Engines • Advantage • Low production cost • Disadvantage • Vehicle motion is required to keep cool

  4. Air cooled Engines • Finned cylinders • Why • Creates more surface area to transfer heat away from the engine • Two stroke engines create more heat because they fire on every revolution • Fan • Not used on all engines • Creates air flow past cylinders to transfer heat • Allows engines to run while standing still

  5. Functions of Coolant • Functions of coolant • Dissipate heat • Prevent rust and corrosion • Lubricates the water pump • Prevent Freezing

  6. Protected with antifreeze Water only Corrosion Protection

  7. Liquid Cooled Engines • Advantages • More consistent operating temperature • More precise engine clearances

  8. Remove Engine Heat • Combustion can reach 4500 ºF • This is hot enough to melt metal parts • Cooling system removes excess heat

  9. 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

  10. Cooling System

  11. Liquid Cooling Heat is transferred to cylinder wall, into coolant and carried away

  12. Types of Coolant • Green • Ethylene glycol based coolant • Invented in 1926 • Toxic • Two ounces of ethylene glycol antifreeze can kill a dog, one teaspoon can be lethal to a cat, and two tablespoons can be hazardous to children.

  13. Types of Coolant • Red • Dexcool • propylene glycol based • Non-toxic at low levels • Protects aluminum components • Prevents cavitation • Prevents corrosion and build up that destroys parts

  14. Coolant Types • Yellow • Used by Ford • Blue • Used by Honda

  15. Coolant Types • Global • Neon Green in color • Safe to mix with any other color • For More info see • http://www.peakantifreeze.com/aboutus.html

  16. Coolant Lowers coolant freezing point to about -34 ºF (-37 ºC)

  17. Impeller Pump Coolant is thrown outward by centrifugal force, producing suction in the center of the pump housing

  18. Water Pump Cutaway Seal leakage will drip from vent hole

  19. Visual Inspection Watch for leakage from bleed holes

  20. Visual Inspection Pump shaft should not wiggle or leak

  21. Radiator and Heater Hoses

  22. Radiator Hoses Two basic types of radiator hoses

  23. Common Hose Problems

  24. Hose Clamps Three basic types of hose clamps

  25. Hose Condition

  26. Radiator Transfers coolant heat to the outside air

  27. Downflow Crossflow Radiator Types

  28. Transmission Oil Cooler Small tank inside one of theradiator tanks

  29. Leaking Radiator

  30. Radiator Cap Pressure Valve • Spring-loaded disk • Normally, water boils at 212 ºF • For each pound of pressure increase, boiling point goes up about 3 ºF • Typical pressure: • 12–16 psi • raises boiling point to 250–260 ºF

  31. Pressure Cap Operation Hot engine

  32. Pressure Cap Operation Cold engine

  33. New Style Overflow Tank

  34. Flex Fan High rpm cause blades to flex, reducing blowing action

  35. Thermostatic Fan Clutch • Bimetal spring controls clutching action • Cold—clutch slips • Hot—clutch locks

  36. Electric Fans • Turned on by • Temp Sending Unit • PCM • Most common fan found today

  37. Thermostat A temperature-sensitive valve

  38. Thermostat Operation

  39. Bypass Valve

  40. Chapter 40 Cooling System Testing, Maintenance, and Repair

  41. Coolant Protection Level • Find what type of coolant is in system • Test the Protection level (-20 to -35°F) • Test PH level • Check overall condition of coolant

  42. PH Test • Check coolant for DC volts • Acidic coolant acts as a battery acid • If above 0.5 volts than coolant is acidic

  43. Dirty Antifreeze

  44. Check for leaks • Hook up pressure tester • Apply 2-3 lbs more pressure than cap will hold • Watch for pressure to drop • Look for leaks

  45. Pressure Testing a Radiator Cap

  46. Coolant Flush • Removes rust and scale • Should be done every other year

  47. Drain Radiator

  48. Cooling System Problems Mineral deposits in water jackets can prevent proper heat transfer

  49. Cooling System Problems A cracked part or blown gasket can allow coolant to leak into the engine oil

  50. Oil and Water Mix

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