I've got a 85 F-150 4x2 302 EFI and lately I've noticed my windows are fogging up quite a bit(not so in the past) primarily when I use my heater. I've tried anti-fog stuff with no luck. the other morning when I started the truck I noticed steam or something (I dont think it was smoke?) coming out of the floor vent. I dont notice any antifreeze leaks on the ground but seem to smell it inside the truck sometimes. I had someone replace the motor last summer(could this be heater hoses???) Any ideas?
Thank you kindly.

 

If your heater core has a small hole in it you will smell antifreeze inside the truck with the heater on. Also your windows will fog more when using the defroster. Your basically blowing mositure on your windshield with a hole in the heater core.

 

Most likely the heater core is leaking. Your not seeing the Antifreeze because its going under your carpet or rubber matting.
You will have to wash your windows real good after replacement of the heater core. Not an easy job. It's up under your dash on the passenger side. It's easier to remove your glove box. And plan on laying on your belly on the passenger side for a while.

 

 

F.W.I.W. I had a little bit of the same problem with mine. I have A.C. so replacing the heater core would be a pretty good job. I tried putting in some Bardahl stop leak and it worked. I just used the small bottle for 4 cyl. engines and it was enough. I know this is only temporary and it may not last. But it might be worth a try to get you through the winter if you don't have time to fix it now. Then you can put it off until the next time you need it.