My 2008 Subaru Impreza has developed a film/residue on the inside of my windows. I mostly notice it on the front and back windows when light is shining through them. I can clean it off with windshield cleaner, but it reappears in less than a week. It didn't do this before winter came around, so this may be related to the defroster/heat.

 

This morning, I warmed up the car (it was 0 degrees) and when I left, I noticed a smell that smelled like something burning.

 

Is this my heater core leaking? I haven't checked my coolant levels. Do I need to have this looked at immediately? I read that coolant smells sweet and I don't think that was what I was smelling this morning.

 

Any help would be appreciated.

If the smell is kind of putrid it could be oil leaking onto the exhaust pipes and burning off.

A split axle boot is also possible and that will fling axle grease on the catalytic converter.

 

A film on the windows during winter is common as moisture in the car condenses on the inside of the windows at night. If there is smoke from burning oil or grease on the exhaust pipes that can work its way into the car through the vents and cause a film as well.

 

Coolant does have a sweet smell. You can open the cap on the overflow bottle and smell the coolant there. If your smell in the cabin is the same, then a heater core leak may be the cause, but I would not suspect a leaking heater core on such a relatively new vehicle.

Most likely the smell is oil or grease burning off of the exhaust. Be sure to check the oil level so it does not run low on oil.

any recent work on the interior? new seat covers or carpet?

 

plasticizers can out-gas and collect on the glass.

Some vinyl conditioners like Armorall can do this, but usually it is worse in summer.  I would check the coolant level, but if that is good, then I would expect the problem to be with the AC.  It is hard to tell in the winter because the AC doesn't actually operate if the evaporator is below 35°F.  That is to keep the coils from icing up.  If your AC stops working, and you should be able to tell once the interior of the car warms up, then that could be the source of the oil.  It would be PAG oil from the freon.