I have a 2008 with the 4.6. Lately when i turn on the heater a mist comes out and the windows almost instantly become fogged over with a film that will only come off with glass cleaner. It is also emitting a sweet smell like syrup. I thought it might be the heater core but the heat is still blowing very hot.
Any input would be appreciated!
thanks
jay

 

It's the heater core.

 

Not sure if it matters or not but i should have added it is not loosing any coolant.

 

Well it may be now, only on of 2 things:

Heater core or evaporator core leaks

 

Classic signs of a heater core leak.. may be small now.. you can try some lucas stop leak..