Coolant Flashcards

Study Notes

Coolant Composition and Function

Coolant primarily consists of water and ethylene glycol, serving as a temperature regulation agent in engines.
Increasing the percentage of antifreeze in coolant lowers the freeze point, enhancing its performance in colder conditions.

Chemical Treatment and Types of Coolants

Coolant can be embittered, meaning a chemical is added to give it a bitter taste, discouraging accidental ingestion.
Asian red coolant is categorized as HOAT (Hybrid Organic Acid Technology).
DEX-COOL is an OAT (Organic Acid Technology) coolant, known for its extended life and specific chemical properties.
PHOAT (Partially Hybrid Organic Acid Technology) coolant is identifiable by its dark green color.

Coolant Chemical Properties

DEX-COOL is free from silicate and phosphate, which distinguishes it from traditional coolants.
Technician A claims that new coolant has a pH above 7, which decreases with engine use, while Technician B notes that OAT and HOAT coolants start with a lower pH than older IAT coolants; both statements are correct.

Manufacturer Guidelines and Testing Methods

Most vehicle manufacturers do not approve the reuse of old coolant, with the exception of Mercedes-Benz.
A voltmeter can be employed to check for issues in coolant; a reading of 0.2 volts when the engine is off and 0.8 volts when running indicates potential problems. Technician B, who suggests inspecting ground wires and connections, is correct.

Physical Properties of Water

Water boils at 212°F at sea level, a critical temperature for engine performance.
Water freezes at 32°F, important for understanding coolant intervention in winter conditions.

Testing and Chemical Reactions

A refractometer is used to assess the freezing point of coolant by examining a few drops on a prism.
Galvanic activity occurs when electric current flows between two metals without an external voltage source, posing risks for coolant systems.
Electrolysis involves electric flow resulting from an external voltage source, potentially causing deterioration in engine components.
Passivation refers to the chemical reaction between coolant and the metal it protects, essential for preventing corrosion and ensuring longevity.

Description

Test your knowledge on coolant properties and types with these flashcards. Each card presents a key term related to coolant and its definition. Challenge yourself and enhance your understanding of automotive cooling systems.