Antifreeze has a sweet smell like pancake or maple syrup. If the smell is noticeable inside the vehicle, the heater core is likely to be leaking. Smelling the sweet scent outside the vehicle indicates that the coolant leak might be in a hose or the radiator.
Regardless of the location of a coolant leak, it is essential to repair it as soon as possible. If the coolant level drops too low, the engine overheats. Overheating often causes major damage to an engine.
Normally, when the coolant leaks outside the car, a puddle accumulates once the vehicle parks. Leaks from the heater core are sometimes more difficult to see. The owner might notice a wet spot on the carpet or a film that forms on the windshield when the defroster operates.