At what temperature does coolant typically boil when pressurized?

Coolant typically boils at a higher temperature when pressurized due to the principles of thermodynamics. In a standard cooling system that is under pressure, the boiling point of the coolant is elevated. For most coolants, including ethylene glycol-based antifreeze, the boiling point at atmospheric pressure is around 212 degrees Fahrenheit. However, when the cooling system is pressurized—often achieved through a radiator cap that maintains pressure—the boiling point can significantly increase.

At pressures commonly found in automotive cooling systems, which can range from 15 to 20 psi (pounds per square inch), the boiling point can rise to around 265 degrees Fahrenheit or even higher, depending on the coolant mixture and system specifications. This increase in boiling point is critical because it allows the engine to operate at higher temperatures without the coolant vaporizing, which could lead to overheating and engine damage.

Therefore, the choice indicating 265 degrees Fahrenheit reflects the elevated boiling point of coolant in a pressurized system, making it an essential characteristic for effective engine cooling under operational conditions.