If your vehicle is showing sweet, syrupy smell coming from the engine bay, here are the most likely causes and the parts you'll need to fix each one.
If the cooling system was recently topped off or serviced, spilled antifreeze on hot engine components will boil off and create a strong, sweet syrup smell.
Rubber coolant hoses degrade, swell, and crack over time due to extreme heat cycles, allowing hot coolant to spray or drip onto the engine.
Modern radiators use plastic end tanks that become brittle and crack with age, causing coolant to seep out and evaporate in the hot engine bay.
When the internal bearing seal of a water pump begins to fail, it intentionally leaks coolant from a 'weep hole' to warn you before a catastrophic failure occurs.
Plastic thermostat housings frequently warp or crack, and their rubber gaskets flatten out over time, allowing coolant to pool on the hot engine block.
Hoses routing hot coolant to the cabin's heater core can leak near the firewall, producing a strong sweet smell at the back of the engine bay that often enters the cabin.
On certain engine designs (especially V6 and V8 engines), the intake manifold gasket seals coolant passages. When it fails, coolant seeps directly onto the hot engine valley.
A catastrophic failure where the head gasket ruptures, allowing coolant to leak externally down the side of the hot engine block or burn inside the cylinders.