Around the end of September, my father and I noticed antifreeze leaking from under the Right Rear of the car. Didn't think much of it, considering that's where the exhaust is, but as the weather got colder, the rear vents would not blow any hot air at all. We Burped the coolant system, and noticed the system was losing coolant pretty fast. So we checked around, I did some searching, and found out it was the heater core in the rear. We ordered one from Ebay, and had a family friend help us replace it. I do NOT recommend doing this yourself, as we had to tear the side panel off and let loose some Freon to install the new core. We got everything installed and put back into place, and a year later, its still running strong. Good luck, and Happy Tinkering!