Single mom not much $

Gas filler is either on the left or right rear quarter panels, possibly behind th elicense plate. The heater core, you need to follow the heater hoses under the hood to find out where itis located.

The fuel filter is located on the passengers side under car, right in front of the fuel tank. The heater core is located behind the dash and the dash assembly has to be removed to access the heater box where the core is located. Is the heater core leaking? Coolant leaking onto passengers side floor? You dont necessarily need a new heater core for a no heat condition. First thing I would do is check the coolant level in the radiator and overflow tank. You could have a bad thermostat or the hot cold blend door might be malfunctioning. Hope this helps