What could a sweet smell from the engine bay mean when it's warm?

[Eleanor.T]

I was topping up my windshield washer fluid the other day and noticed a faint, sweet smell coming from the engine bay when it was warm. My car isn’t overheating and the coolant level looks okay, but that scent has me a bit worried. Has anyone else had this happen just before a small leak or something more serious showed up?

[James70]

That sweet smell in a warm engine bay often means coolant is touching hot metal or a tiny leak is starting up.

[Aurora_J]

Sweet coolant odour usually means ethylene glycol is present and a small leak in the cooling system or a loose cap is letting vapor escape.

[RobertVT]

Perhaps the scent is not a leak at all but a mis identified odor from windshield washer fluid fumes heating up near the engine while you were topping it up.

[Violet_L]

What if the real issue is a venting or routing quirk that lets a coolant smell spread when the engine warms rather than a drip somewhere.

[StevenG]

Do a quick check for puddles under the car and peek at the coolant reservoir when the engine is cold then a pressure test if the level looks steady.

[Aubrey9]

I would be uneasy and would not ignore it even if the gauge looks fine because a small leak can grow.

[Kevin71]

If you want a path forward ask a shop to run a dye test in the cooling system to locate any tiny leak and rule out heater core or hose faults.