I've been losing coolant for some time now- not a lot, just enough that it needs to be refilled every few weeks. And in January of this year, I began having trouble with my heater - running it would cause an unusual fog to appear on the inside of my windshield that couldn't be easily wiped off. Today I noticed that there is a LOT of oil (?) on the passenger side floorboard underneath the mat (and now on the mat a bit).

I am not at all mechanically inclined, but I have done some research this evening and it looks like perhaps my heater core has ruptured and the "oil" is coolant that has leaked into the passenger compartment.

Does that sound like the most likely issue?

Is there any type of safety issue? I do not want to spend what it will take to fix it - at least right now - and the temps here are fairly warm so I could probably get by without it. But I need to be sure it's OK to ignore it until I can sell it, trade it in, or get the heater core replaced.

Thank you!

Definitly heater core. I would at least by pass the heater core so you dont ruin your carpet, and other items. lots of labor involved in replacement.

i had a problem with the a/c one time that leaked oil on the passenger floorboard. there was a leak in the evaporator and the ac oil dripped out. is your a/c working well?