Why do you smell antifreeze when heat is on?

If you smell antifreeze when your vehicle's heat is on, it may indicate a coolant leak in the heating system. This can occur due to a damaged heater core, which is responsible for transferring heat from the engine coolant to the air blown into the cabin. A leak can allow coolant vapors to enter the vehicle's interior, creating a sweet, pungent smell. It's important to address this issue promptly, as it can lead to engine overheating and other serious problems.