Coolant emptying every couple of days?

you mentioned a weired smell through the vents feel the carpet on the penger side of your car under the floor mat, this probably sounds weired to you but not to a mechanic see if it is wet and if it is you need to replace your heater core. also you can go to the yellow pages and call a radiator repair shop and ask them if they can put a pressure pump on your cooling system and by doing this they can nail your leak 100% accurate,and normally for free if you let them repair it ,also a lot cheaper than most garages. 40 plus years in the auto field.