A coolant smell from a vehicle is often described as a sweet or syrup-like odour. This smell usually indicates that coolant, also known as antifreeze, may be leaking from the engine cooling system.
The cooling system is responsible for regulating engine temperature and preventing overheating. Coolant circulates through the engine and radiator, absorbing heat and releasing it through the radiator. If coolant escapes from the system, the engine may eventually overheat and suffer serious damage.
Drivers often notice the smell when the engine is warm or after driving. In some cases the smell may also appear inside the cabin if coolant leaks from components connected to the vehicle’s heating system.
The most common cause of a coolant smell is a leak somewhere in the cooling system. Over time hoses, seals and plastic components can degrade or crack due to heat and pressure.
When coolant leaks onto hot engine components it may evaporate quickly and produce the sweet smell associated with antifreeze.
If the coolant smell appears inside the cabin, the heater core may be leaking. The heater core is a small radiator located behind the dashboard that uses hot coolant to warm the interior of the car.
A failing heater core may also cause fogging on the inside of the windscreen or leave a sticky film on interior glass surfaces.
Radiator cracks, loose hose connections or deteriorated coolant hoses can also allow coolant to escape from the system. These leaks may sometimes leave visible puddles underneath the vehicle.
If a coolant smell continues or becomes stronger, the cooling system should be inspected as soon as possible. Low coolant levels can lead to engine overheating which may cause expensive engine damage.
Checking coolant levels regularly and inspecting the radiator, hoses and engine bay for leaks can help prevent further problems.
Other smells may indicate different mechanical issues. For example a burning smell from the car may indicate overheated components, while a burning oil smell may suggest an oil leak contacting hot engine parts.
MotorLoom analyses vehicle symptoms, smells and warning lights to help identify possible causes.
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