gas smell coming from heater

So what smell are you smelling is it sweet?Is the carpet in the front getting wet up by your feet?

The smell is the smell of gasolinee fumes when the heater is on. So me times gas smell is very from slight to strong.

Well a heater core or evaporator core doesn't have or leak gasoline.You must have a gas leak under the hood and the blower fan is bringing the smell in.I would be looking in the engine compartment when the smell is present.

Again, thank you for your speedy advice, the problem seems to have gone away. I just bought the car and i believe it sat in the garage for awhile. This is my first volvo and im still getting to know the car. Thank you.

Well keep me posted if you find something or the smell comes back.