About 4 times in the last two winters when I turn the defrost on full blast and lets say punch it a little bit like getting on the interstate or highway it almost instantly fogs up the windshield. So bad that I can barely see out. also it smells a little like antifreeze. but it doesn't do it all the time and I don't smell the antifreeze all the time. ant ideas

 

Heater core leaking.