Which component is used to release air trapped in the cooling system?

Which component is used to release air trapped in the cooling system?

• A. Radiator cap
• B. Bleeder screw
• C. Thermostat
• D. Water pump

Answer: (B)

Air trapped in the cooling system reduces heat transfer and can cause overheating because air pockets don’t carry heat like coolant. To purge that air, a bleeder screw is opened at the highest point of the cooling system during filling. This lets air escape until only coolant flows, indicating the air has been purged, and then the screw is closed. The radiator cap mainly maintains system pressure and vents excess pressure; it isn’t used for regular air removal. The thermostat controls when coolant flows based on temperature, and the water pump circulates the coolant. So, the component used to release trapped air is the bleeder screw.

Air trapped in the cooling system reduces heat transfer and can cause overheating because air pockets don’t carry heat like coolant. To purge that air, a bleeder screw is opened at the highest point of the cooling system during filling. This lets air escape until only coolant flows, indicating the air has been purged, and then the screw is closed. The radiator cap mainly maintains system pressure and vents excess pressure; it isn’t used for regular air removal. The thermostat controls when coolant flows based on temperature, and the water pump circulates the coolant. So, the component used to release trapped air is the bleeder screw.