Ford Repair: 97 Ford Explorer xlt 4dr 4.0 sohc, ford explorer xlt, water leaks

Question
QUESTION: Just entering winter season & my inside windows are fogging up a few seconds after I start vehicle. I have to blast the defrost to clear condensation on windshield. I have checked for water leaks,none, carpets all dry, no water running down firewall inside or out (that I can see). I did notice my rad overflow bottle is very low(car was warm still). I do smell anti-freeze from time to time, but outside car only. Have good heat & a/c is chilling.

ANSWER: watch windshield after shutting off on a cold day about 30 minutes to an hour after parking it see if moisture gathers on inside of windshield
if so you may have a core seeping-make sure your control is set to outside air and not recirculate when on defrost-all three of my vehicles fog some within 2-3 minutes but goes away quickly. i would be  very suspicious of that core. good luck.

---------- FOLLOW-UP ----------

QUESTION: Should I be changing the heater core or live with it for now? I did suspect heater core initially but as no leak inside veh made me wonder. As I do have pass airbag, do I have to pull dash & air bag to change or is it accessible with glove box out? Or is it changed from under hood(god forbid,all the a/c stuff in the way, yuk

Answer
i would definitely verify for sure about the heater core before doing this job-but it does look like that is the problem-this is a 6.5-8.0 hour job-so be sure of the leak and please use a good quality part you don't want to do this one a second time-be sure coolant is clean and body to engine ground is connected and if your core has a ground make sure and reconnect it otherwise electrolysis will eat it up. if you don't have patience don't tackle it. you can go to alldata.com and buy a one year subscription for about 34-39 dollars it will have all instructions plus all kind of info on your truck. good luck