The air-conditioning evaporator is a small radiator inside the dashboard that provides cold air for the air-conditioning system. It’s called the evaporator because it’s where the freezing liquid refrigerant takes on any heat from the air blown through it and changes into a gaseous state (evaporating it) before returning it to the air-conditioning condenser to shed the heat; the process is constantly repeated. The air that emerges from the air conditioner is cold as a result.

The evaporator is typically hidden inside the vehicle’s dashboard and can be labor-intensive to replace, which then requires a full system recharge. Unlike a ruptured heater core, which can leak engine coolant into the foot wells, a leak in the evaporator releases only refrigerant vapor. A clogged drainage channel is a common cause of water in the front foot wells.

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