I've noticed that my coolant seems to be disappearing on me. I topped up my rad a couple of weeks ago, drove for a while and now it needs more fluid. I've checked for leaks (none), there's no puddle under the passenger feet (replaced heater core in spring) but I have noticed a strong smell of coolant when i put the heat on in the morning. Kind of like it's burning. Could I possibly have a head gasket problem? I didn't notice anything in the oil either.

 

Is the passenger side front floor wet?