I start my 97 F150 xlt 4x4 4.6 liter with the heater and A/C in the off position. About a minute or so later, I start to smell antifreeze and can see fumes and a light fog coming from my heater/AC vents. Smells really bad! I am afraid to drive it because the fumes cannot be good for the lungs. Someone please point me in the right direction. I think it might be the heater core, but I know that is a real pain to remove and replace.

Eric

 

Yep. Sounds like a heater core. Fogging of the inside is typical of a leaking heater core. Good luck.

 

Been there done that, got the smell.... Blown coil, Antifreeze smell, fog. Ghezzz.
NOTE: Avoid breathing antifreeze fumes, it's toxic. Two days later, done
Left with a lingering smell - what to do.
I pulled the stereo trim and sprayed cleaner inside the vent, Gently poked a rag inside and mopped out the cleaner, took away most of it, over time things will get better.

Good luck Guy's and girls, just remember a 1/4 tea spoon of antifreeze will kill most pets. IT'S TOXIC
Grassybranch -

 

^ But it is so sweet tasting!

 

One thing about antifreeze...if you can smell it, it's leaking.