! have a 1982 F-250 with a 302. I have a problem defogging the windows when I turn on the heat it fogs up the windows with what seams like oily film(fog) that does take an a long time to clear even though the heat in blowing nicely. I tried cracking the windows, running the air conditioner, opening the fresh air vents and nothing works. It also gives off a burn smell when first starts running. and have seen smoke come through the vents a few times messing with the controls trying to clear the windows. My truck also uses the old refridgerant for cooling. I also have fog marks on the front window even if I don't use the heat,or air after driving and never seams to disappear even after long periods of time.

 

if it has a sweet smell to it your heater core is leaking... what is getting on your window is the vapor from the anti-freeze..

 

thats exactly what mine did, didnt smell anything but it was the heater core. when you go to replace it its a great time to take out the blower motor too and clean out all the debre in the vents and near the resistor

 

the burning smell when my truck did it was the crap on the resistor as it cooked it self

 

mine didnt have much of a smell to it either..just on occasion i would get a whiff of the antifreeze.. all it took was the first time to smell it and i knew what it was.. and i bet that is why it was bypassed when i bought it..

 

i have the same problem...mine smells like antifreeze and the windshield fogs like crazy...one way that i noticed is that if you look in the engine bay on the side where the heater core is you may seem water leaking from a gromet that goes to the cab.

 

Welcome to the forum, sruiz2169!

 

thanks...

 

i have the same problem but i just changed my heater core. it does the same thing even with the new one.

 

my brother had that same problem and it was his heaer hose leaking at the heater core

 

It doesn't take much anti freeze to cause your problem. Once the heater core is replaced all the ducts will need to be cleaned. If you don't smoke in the rig, plain water on a white Costco towel works great to clean the windows with no residue.