Question

The coolant in an automobile radiator is kept at a pressure higher than atmospheric pressureT. Why is this desirable? The radiator cap will release coolant when the gauge pressure of the coolant reaches a certain value, typically or so. Why not just seal the system completely?

Short answer

Answer

Keeping the pressure higher thanatmosphericpressure is desired because the increase in pressure increases theboilingpoint of thecoolantand protects the engine from any damage.

Step-by-step solution

About Coolant in automobile radiators  

A chemical used to keep the temperature of the engine in the operating range is known as Coolant. It is made from either ethylene glycol or propylene, water, and some protection additives and is usually green, blue or even pink in colour.

Determine why The coolant in an automobile radiator is kept at a pressure higher than atmospheric pressure

The pressure at which the coolant is kept inside the radiator is always higher than the atmospheric pressure. This is due to an increase in pressure, which increases theboilingpoint of thecoolant.so thecoolantcan transfer the heat at a hightemperaturewhich in turn makes the engine cooling more efficient.

When the engine runs for a long time thetemperatureof the radiators keeps on increasing and it might damage the engine, therefore, for the safety of the engines and other parts, thecoolantis kept at certain gauge pressure when thepressureof thecoolantreachesa certain point the radiator cap isreleasedand hotcoolantcomes out of the cooling system. Hence, total heat isdecreased. Therefore the engine and other parts are saved.

If we seal the radiator cappermanentlythen theradiatorpressure will keep on increasing and some parts of the engine may damage due to high pressure. Therefore keeping the pressure higher thanatmosphericpressure is desired as it increases theboilingpoint of thecoolant.