Or someone in the back seat farted. Define weird - anti-freeze has kind of a sweet smell - that would probably be a leaking heater core (under the dash) check for wetness in the front foot wells - wet carpet.

It's probably the heater core leaking inside the cabin. Check around the passenger floorboard and firewall for coolant.

Going to have to define smell. Antifreeze is sweet smell, catalytic converter spoiled eggs, oil burnt, etc. What is smell and when do you smell it

No such thing as a "radiater".