There is a fuel leak in the engine compartment. Have a mechanic look at the engine.
A burning smell from a car's brakes means that you are braking very hard or there is a electrical short circuit in the car. Another reason for a burning smell may actually be coming from the car's heater.
You have either a cracked heater core or bad heater hoses that are allowing antifreeze to enter into the vehicle............
You most likely have a leak or your car is overheating. If you are smelling it in the car then in all probability the heater core is leaking.
If you smell antifreeze in the passenger compartment of your car your heater core is probably leaking. It's under the dash somewhere ( depends on the make and model ). Another symptom of a leaking heater core is moisture build up on the inside of the windshield when you run your defroster.
That "mist" is more than likely coolant steam coming from a leaky heater core. Replacing the heater core is your best option.
Depends on the smell. if it smells sweet, like antifreeze, then it is probably a leak in the heater core. This is a small radiator that runs from the main radiator and makes hot air for the heater. If it smells like gasoline, may be a gas leak. Do not drive the car, get it fixed by a professional. If it smells like smoke, it may be an oil leak. get it checked.
It is possible that a car can smell like gas when the heater is turned on for a few reasons. One possible reason that this happens could be a leak in the line.
more then likely your heater core has a hole in it do you smell a sweet smell coming from the same area or see any anti-freeze if so you need to replace your heater core
If the car heat has a fresh air setting, then it could be drawing air from outside of the vehicle. The fumes are most likely coming from a problem under the hood.
Bad heater core >>> Check for coolant on the passenger side front, just under the glove compartment floor. Bad head gasket >>> Check for coolant mix with the motor oil.
Leaking heater core
dryer sheets in the heater vents may help