Could be your heater core leaking - stick your fingers under the front edge of the carpet in the right front passenger area and see if its damp (caution : don't lick your fingers afterwards )
if you smell it inside, it's the heater core it has a leak.
You have a coolant leak.
Bacterial growth causes your navel to smell.
If you smell antifreeze, there must be a leak somewhere. Have the cooling system pressure tested.
It probably has a leak, possibly from the heater core.
usually you will get antifreeze smell and steam inside coming from defrost
Some people say that the smell of hot antifreeze smells like mold. It could be possible you are smelling the antifreeze from the engine.
leaking heater core
i believe your heater core has died
Your heater core may have a leak in it, allowing the fumes to invade the inside of the vehicle.
You have a leak in the heater core. The heater core is the only place that radiator water enters the truck cab, and both foggy windows and antifreeze odor are common indicators.
your vehicle may smell like antifreeze while driving because it is overheating