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CHAPTER 13 COOLANT

CHAPTER 13 COOLANT. OBJECTIVES. After studying Chapter 13, the reader should be able to: Prepare for ASE Engine Repair (A1) certification test content area “D” (Lubrication and Cooling Systems Diagnosis and Repair). Describe the various types of antifreeze coolants.

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CHAPTER 13 COOLANT

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  1. CHAPTER 13 COOLANT

  2. OBJECTIVES After studying Chapter 13, the reader should be able to: • Prepare for ASE Engine Repair (A1) certification test content area “D” (Lubrication and Cooling Systems Diagnosis and Repair). • Describe the various types of antifreeze coolants. • Discuss how to store, recycle, and discard used coolant. • Discuss how to test coolant.

  3. DEX-COOL Electrolysis Embittered coolant Ethylene glycol based coolant Galvanic activity Hybrid organic acid technology (HOAT) Inorganic acid technology (IAT) Organic acid technology (OAT) Passivation Phosphate hybrid organic acid technology (PHOAT) Refractometer KEY TERMS

  4. FIGURE 13–1 Graph showing the relationship of the freezing point of the coolant to the percentage of antifreeze used in the coolant. COOLANT FUNDAMENTALSPURPOSE OF COOLANT • Coolant is used in the cooling system because it: • Transfers heat from the engine to the radiator • Protects the engine and the cooling system from rust and corrosion • Prevents freezing in cold climates

  5. COOLANT FUNDAMENTALSFREEZING/BOILING TEMPERATURES • It should be noted that the freezing point increases as the antifreeze concentration is increased above 60%. • The normal mixture is 50% antifreeze and 50% water. • Ethylene glycol antifreeze contains: • Anticorrosion additives • Rust inhibitors • Water pump lubricants

  6. FIGURE 13–2 Graph showing how the boiling point of the coolant increases as the percentage of antifreeze in the coolant increases. COOLANT FUNDAMENTALSFREEZING/BOILING TEMPERATURES

  7. COOLANT FUNDAMENTALSCOOLANT COMPOSITION • All manufacturers recommend the use of ethylene glycol based coolant, which contains: • Ethylene glycol (EG): 47% • Water: 50% • Additives: 3%

  8. TYPES OF COOLANT • INORGANIC ACID TECHNOLOGY • ORGANIC ACID TECHNOLOGY • HYBRID ORGANIC ACID TECHNOLOGY • PHOSPHATE HYBRID ORGANIC ACID TECHNOLOGY • UNIVERSAL COOLANT

  9. FIGURE 13–3 Havoline was the first company to make and market OAT coolant. General Motors uses the term DEX-COOL. TYPES OF COOLANT

  10. FIGURE 13–4 Coolant used in Fords that use Mazda engines and in Mazda vehicles. It requires the use of a PHOAT coolant which is dark green. TYPES OF COOLANT

  11. What Is a “G” Coolant? • The “G” coolants come from the trade name Glysantin of BASF in Europe and Valvoline (Zerex) in the United States. The following is a summary of the types listed by G number. • G05: different from DEX-COOL in certain amounts of additives • G30 and G34: nonsilicate and phosphate free • G11: blue VW used before 1997 • G12: pink/red VW 1997 (purple VW 2003) • HOAT formulation • Phosphate free • G48: low silicate and phosphate free • Blue • Nitrates, amines, phosphate (NAP) free

  12. What Is “Pet Friendly” Antifreeze? • Conventional ethylene glycol antifreeze used by all vehicle manufacturers is attractive to pets and animals because it has a sweet taste. Ethylene glycol is fatal to any animal if swallowed, so any spill should be cleaned up quickly. There are two types of coolant that are safer for use around pets than the conventional type. • Propylene glycol (PG). • Embittered coolant.

  13. FIGURE 13–5 Not all embittered coolant is labeled embittered. What Is “Pet Friendly” Antifreeze?

  14. If 50% Is Good, 100% Must Be Better • A vehicle owner said that the cooling system of his vehicle would never freeze or rust. He said that he used 100% antifreeze (ethylene glycol) instead of a 50/50 mixture with water. • However, after the temperature dropped to 20°F (29°C), the radiator froze and cracked. (Pure antifreeze freezes at about 0°F [18°C]). After thawing, the radiator had to be repaired. The owner was lucky that the engine block did not also crack. • For best freeze protection with good heat transfer, use a 50/50 mixture of antifreeze and water. A 50/50 mixture of antifreeze and water is the best compromise between temperature protection and the heat transfer that is necessary for cooling system operation. Do not exceed 70% antifreeze (30% water). As the percentage of antifreeze increases, the boiling temperature increases, and freezing protection increases (up to 70% antifreeze), but the heat transfer performance of the mixture decreases.

  15. What Makes Some Water Bad for Coolant? • City water is treated with chloride, which, if the levels are high enough, can cause corrosion problems when used in coolants. Well water may contain iron or other minerals that can affect the coolant and may increase the corrosion or cause electrolysis. Due to the fact that the water quality is often unknown and could affect the engine, many vehicle manufacturers are specifying the use of pre-mixed coolant. In premix coolant, the water is usually de-mineralized and meets the standards for use in coolant.

  16. WATERINTRODUCTION • Water is half of the coolant and can have an effect on the corrosion protection of coolant due to variations in its quality, which is often unknown.

  17. WATERPROPERTIES • Water is about half of the coolant and is used because of the following qualities. • It is inexpensive. • It is an efficient heat exchange fluid because of its excellent thermal conductivity (the ability of a material to conduct heat). • It has good specific heat capacity, meaning it takes more heat energy to increase the temperature, versus one with low specific heat capacity. • The boiling point is 212°F (100°C) (at sea level). • The freezing point is 32°F (0°C).

  18. COOLANT FREEZING/BOILING TEMPERATURES • FREEZING POINT • Pure water • 32°F (0°C) • Pure antifreeze* • 0°F (-18°C) • 50/50 mixture • - 34°F (-37°C) • 70% antifreeze/30% water • - 84°F (-64°C)

  19. Why Is Most Coolant 50/50 with Water? • According to the freezing point, it appears that the lowest freezing point of coolant is achieved when 70% antifreeze is used with 30% water. While the freezing temperature is lower, the high concentrate of antifreeze reduces the heat transferability of the coolant. Therefore, most vehicle manufacturers specify a 50/50 mixture of antifreeze and water to achieve the best balance between freeze protection and heat conductivity.

  20. COOLANT FREEZING/BOILING TEMPERATURES • Boiling Point at Sea Level • Pure water • 212°F (100°C) • 50/50 mixture • 218°F (103°C) • 70/30 mixture • 225°F (107°C) • Boiling Point with 15 PSI Pressure Cap • Pure water • 257°F (125°C) • 50/50 mixture • 265°F (130°C) • 70/30 mixture • 276°F (136°C)

  21. COOLANT TESTING • Normal coolant tests include: • Visual inspection. Coolant should be clean and bright. • Freeze/boiling point. A high freezing point or low boiling point indicates dilution (too much water). • pH. The wrong pH indicates buffer loss, which is used to help maintain the pH level. • Coolant voltage. A high voltage indicates the wrong pH or a stray current flow.

  22. COOLANT TESTING • HYDROMETER TESTING • REFRACTOMETER • PH • GALVANIC ACTIVITY • ELECTROLYSIS • TESTING FOR GALVANIC ACTIVITY AND ELECTROLYSIS • TEST STRIP TESTING

  23. FIGURE 13–6 Checking the freezing temperature of the coolant using a hydrometer. COOLANT TESTING

  24. FIGURE 13–7 Using a refractometer is an accurate method to check the freezing point of coolant. COOLANT TESTING

  25. FIGURE 13–8 A meter that measures the actual pH of the coolant can be used for all coolants, unlike many test stripes that cannot be used to test the pH of red or orange coolants. COOLANT TESTING

  26. FIGURE 13–9 Galvanic activity is created by two dissimilar metals in contact with a liquid, in this case coolant. COOLANT TESTING

  27. FIGURE 13–10 A test strip can be used to determine the pH and percentage of glycol of the coolant. The percentage of glycol determines the freezing and boiling temperatures, as shown on the bottle that contains the test strips. COOLANT TESTING

  28. COOLANT REPLACEMENT ISSUES • INTERVALS • PASSIVATION • RECYCLING COOLANT

  29. SUMMARY • All coolant is ethylene glycol based. Some aftermarket coolants use propylene glycol. • Used coolant should be recycled whenever possible. • The freezing temperature of the coolant can be tested using a hydrometer or refractometer. • Proper cooling system maintenance usually calls for replacing the coolant every two years or every 24,000 miles (36,000 km) for IAT coolant but longer for OAT, HOAT, and PHOAT coolants.

  30. REVIEW QUESTIONS • What types of coolant are used in vehicles? • Why is a 50/50 mixture of antifreeze and water commonly used as a coolant? • What are the differences among IAT, OAT, HOAT, and PHOAT coolants? • What are some of the heavy metals that can be present in used coolant? • What is the difference between galvanic activity and electrolysis?

  31. CHAPTER QUIZ 1. Coolant is water and ________. • Methanol • Glycerin • Kerosene • Ethylene glycol

  32. CHAPTER QUIZ 2. As the percentage of antifreeze in the coolant increases, ________. • The freeze point decreases (up to a point) • The boiling point decreases • The heat transfer increases • All of the above

  33. CHAPTER QUIZ 3. Adding a chemical to make ethylene glycol coolant bitter to the taste is called ________. • Passivation • Embittered • Refractometer • Electrolysis

  34. CHAPTER QUIZ 4. Asian red coolant is what type? • IAT • OAT • HOAT • PHOAT

  35. CHAPTER QUIZ 5. DEX-COOL is what type of coolant? • IAT • OAT • HOAT • PHOAT

  36. CHAPTER QUIZ 6. PHOAT coolant is what color? • Dark green • Red • Orange • Blue

  37. CHAPTER QUIZ 7. DEX-COOL is ________. • Propylene glycol • Ethylene glycol • Is silicate and phosphate free • Both b and c

  38. CHAPTER QUIZ 8. Two technicians are discussing testing coolant for proper pH. Technician A says that coolant has a pH above 7 when new and becomes lower with use in an engine. Technician B says that OAT and HOAT coolants have a lower pH when new compared to the old green IAT coolant. Which technician is correct? • Technician A only • Technician B only • Both Technicians A and B • Neither Technician A nor B

  39. CHAPTER QUIZ 9. Reusing old coolant is generally not approved by vehicle manufacturers except ________. • General Motors • Ford • Chrysler • Mercedes

  40. CHAPTER QUIZ 10. A voltmeter was used to check the coolant and a reading of 0.2 volt with the engine off was measured. A reading of 0.8 volt was measured with the engine running and all electrical accessories turned on. Technician A says that the coolant should be flushed to solve the galvanic activity. Technician B says that the ground wires and connections should be inspected and repaired to solve the electrolysis problem. Which technician is correct? • Technician A only • Technician B only • Both Technicians A and B • Neither Technician A nor B

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