Question

Why are radiator caps pressurized?

A) to allow the coolant to circulate
B) to control the coolant flow
C) to prevent vapor lock
D) to raise the Boiling point of the coolant

Answer 1

Radiator caps are pressurized to raise the boiling point of the coolant, allowing the engine to operate at higher temperatures and improving cooling efficiency. Expansion calculations involving the volume coefficient are necessary to determine overflow volume due to heat.

Step-by-step explanation:

Radiator caps are pressurized primarily to raise the boiling point of the coolant. This happens because the pressurized system increases the boiling point above that of water's normal boiling point at atmospheric pressure. This allows the engine to operate at higher temperatures without the risk of the coolant boiling, which would significantly reduce its ability to transport heat away from the engine. As an additional benefit, this helps prevent boiling over of the coolant and improves overall cooling system efficiency. When it comes to the expansion of the radiator fluid, the volume of fluid that will overflow when the radiator and fluid reach their operation temperature can be calculated using the volume coefficient of expansion. Using the provided coefficient (ß = 400×10-6°C) and the volume change from 10.0°C to 95.0°C, one can determine the increased volume due to thermal expansion and the consequent overflow volume.