Cooling System Functions

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

5. Protected with antifreeze Water only Corrosion Protection

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

7. 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

8. Cooling System

9. 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.

10. 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

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

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

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

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

15. Radiator and Heater Hoses

16. Common Hose Problems

17. Hose Condition

18. Downflow Crossflow Radiator Types

19. Leaking Radiator

20. 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

21. Pressure Cap Operation Hot engine

22. Pressure Cap Operation Cold engine

23. New Style Overflow Tank

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

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

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

27. Thermostat A temperature-sensitive valve

28. Thermostat Operation

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

30. 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

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

32. Dirty Antifreeze

33. 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

34. Pressure Testing a Radiator Cap

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

36. Drain Radiator

37. Oil and Water Mix

38. Belt Types • V- Belt • Seldom used today • Serpentine Belt • Most common • Runs multiple pulleys

39. Belt Facts • Serpentine Belt • 1979 Ford Mustang the first to use • Saved 3" to the front of the car • Saved 28 lb in total weight of the car • Cam about because of oil crisis

40. Belt Inspection • Check tension • Check for cracks • 3 cracks/inch = 80% belt life gone • Check for wear

41. Belt Test • Belt Squeal • Spray water on the belt • If the squeal goes away • Misalignment Problem • If the squeal continues • Tension Problem

42. Automatic Tensioner • Spring tensioners • Along with the tension spring there is also a dampener which acts like a shock absorber • To inspect the tensioner • Look for rust bleed • Spring is cracked or broken • Cracked arm • Tensioners failing at 50 to 60 thousand miles