Chapter 20 - Coolant

Question 1

Coolant composed of:
47% ethylene glycol
50% water
3% Additives

Answer 1

Ethylene Glycol-based Coolant

Question 2

Contains ethylene glycol but does not contain silicates or phosphates. Usually orange in color

Answer 2

Organic Acid Technology (OAT)

Question 3

A variation to OAT coolant in that it uses carboxylates (organic acid salts) yet provide the correct PH

Answer 3

Hybrid Organic Acid Technology (HOAT)

Question 4

Conventional coolant used for over 50 years. Generally green in color and contains inorganic salts such as sodium silicate, phosphates, and borates. Silicates have been found to be erosive to water pump impellers

Answer 4

Inorganic Additive Technology

Question 5

Causes scaling and reduces heat transferability of coolant

Answer 5

pH too high, or alkaline

Question 6

Causes corrosion of engine components exposed to coolant

Answer 6

pH too low, or acidic

Question 7

Coolant with a small amount of substance added to make it taste bitter

Answer 7

Embittered Coolant

Question 8

Usually a HOAT, with extended life and a low-silicate, phosphate-free coolant

Answer 8

Universal Coolant

Question 9

Boiling point of water

Answer 9

212°F/100°C

Question 10

Freezing point of water

Answer 10

32°F/0°C

Question 11

Freezing point of 50/50 antifreeze

Answer 11

-34°F/-37°C

Question 12

Amount boiling point is increased per 1 PSI pressure

Answer 12

3°F

Question 13

Ideal freezing point and boiling point of coolant (including pressure cap)

Answer 13

Below -20°F and above 234°F

Question 14

Standard coolant pH

Answer 14

IAT: 7.5 - 10

OAT, HOAT, and PHOAT: <7.5

Question 15

Flow of electrical current as a result of two different metals in a liquid (like a battery). Requires no outside voltage source

Answer 15

Galvanic Activity

Question 16

Chemical decomposition requiring the use of an outside voltage source

Answer 16

Electrolysis

Question 17

Coolant replacement intervals

Answer 17

OAT/HOAT: 5 years or 150k miles
Japanese Vehicles: 3 years or 36k miles
IAT: 2 years or 24k miles

Question 18

Chemical reaction that takes place between coolant additives and the metal it protects, forming a barrier between coolant and engine metal. Reason for recommendation to not change coolant types

Answer 18

Passivation