Examkin

Question

Difficulty: EasyCooling System

In an automotive liquid cooling system, what is the primary mechanical purpose of mixing antifreeze with water?

  1. A
    Regulating the flow rate of coolant into the radiator based on operating temperature
  2. B
    Generating electric current to keep the vehicle battery fully charged during operation
  3. Lowering the freezing point and raising the boiling point of the engine coolantAnswer
  4. D
    Balancing the ratio of intake air and fuel delivered to the engine combustion chambers

Answer

Lowering the freezing point and raising the boiling point of the engine coolant
Mixing antifreeze (typically ethylene glycol or propylene glycol) with water creates an effective coolant that lowers the freezing point to prevent engine block damage in cold temperatures and raises the boiling point to prevent overheating during high-temperature operation.

Step-by-Step Solution

1
Identify the primary chemical and functional role of antifreeze (ethylene glycol) in automotive engines.
Antifreeze changes the thermal properties of plain water when mixed in standard proportions.
Water alone freezes at 32°F (0°C) and boils at 212°F (100°C), which is inadequate for the thermal extremes of an internal combustion engine.
2
Evaluate the effect of the mixture on liquid operating limits.
The solution prevents the coolant from expanding and freezing in winter while raising the boiling point to resist vaporizing under high engine temperatures.
A 50/50 mixture provides protection against both extreme cold cracking the block and extreme heat causing boiling.

Key Concept

Coolant mixture properties and thermal protection
Estimated Time:45s
Rate this question

Topics

Cooling System

More questions from this topic