Oldsmobile/Buick Repair: 1999 Oldsmobile Bravada, oldsmobile bravada, air cond

Question
I have a 1999 Oldsmobile Bravada  (4.3l) AWD.  The defrost does not work and when turned on you can smell antifreeze.  Also, if you run the heat the windows will fog up b/c of the moisture.  Does this sound like the heater coil is bad?  If so, how bad is it to replace?  If not, please advise what it could be.  Note that the vehicle is not overheating (as of yet).  

Answer
hi david,yes definately is a heater core,well i don,t know how much detail you are willing to go into.or what you are comfortable with doing as far as repairs.but it is conciddered to be pretty in depth .the heater core is in the heater box.big black thing that you see under the dash.the heat and air cond evaporator are both in there and the a\c most likely would need discharged and recharged.i would say only you know if you want to tackle this job.but there is a lot of things that could go wrong and a lot of screws and brackets hoses etc.hope this helps ty please take a min to rate my service ty billymac