I recently bought a 1997 Subaru Outback. There is a burning smell sometimes and can’t quit put my finger on any specific time that this occurs. Also, I find the heat is really crummy. Takes a very long time to heat up and never gets really warm. I might add that when I bought this car the air conditioning “condenser” was not hooked up. It came with the car and looks like a small radiator. Could this have anything to do with either problem?
A burning smell may be oil residue from a leak here or there finding something hot. Not uncommon for a 17 yo car. The crummy heat could be a bad thermostat, air in the heater core, or a clog in the heater core. A disconnected condensor coil should not affect any of this.
For the heater, look at the temp gauge. If it stays below the middle of the gauge, the thermostat is most likely bad. If it gets to the middle, but remains crummy, there is either an air bubble or a clog preventing coolant from flowing through the heater core.
Can you return the car and get your money back? You should if you can.