I'm not a mechanic / technician but it sounds like your heater core is leaking
Have you noticed if your engine coolant level is going down ?
your heater core has got a leak and needs to be replaced
Telltale sign is WHITE smoke coming from the exhaust that smells like Antifreeze.
The smoke is actually antifreeze mixed with air. The most common cause of this is a leaky heater core.
Condensation in the exhaust train is perfectly normal. It should dry out after several minutes. If it smells like antifreeze, suspect a bad head gasket.
If you mean "why", then the answer is that there is a leak in the heater core.
Have you spilt some on the radiator?
smell of antifreeze and no visable leaks usually indicates that the heater core needs replacing
Could be that your head gasket is beginning to go. Does it smell strongest when you first start the car, then go away? Look for excess steam coming out the tailpipe when you first start it.
if it smells like antifreeze inside the cockpit then your problem is the heatercore, since you can't see it.
If it's in the front floorboard and smells like antifreeze, then your heater core is leaking. If it's plain water, it may be the windshield. There is also a hose that drains the condensation that goes through the firewall. Make sure it's clear and has no buildup.
It is a 1998 Chevy Blazer. I don't know how I posted this topic in the first place???
your heater core is probably bad.