There is a smeary film on the interior of my windshield and back window. No matter what I use to clean it, it returns quickly. I notice it in other people’s cars, also. It is especially noticable when the sun shines directly into it. What causes this and how can I make it go away?
Several things can cause this.
Smoking is a big one.
A heating core leak.
Also very common is the use of Armorall and such vinyl protecting products. These products off-gas and their off-gassing leaves a residue on the windows.
Mike has a very good list there.
My 98 buick did the same thing for the 6 years I owned it. No smokers, never used armour all, etc. THe only thing I found that helped was leaving the windows cracked, it ventilated the inside. I guess the materials in the cockpit were still “gassing” for all that time. I do know it seemed worse in the winter, but that’s when the car windows were closed more and there was less outside ventilation Also the car was really good at providing static electrical shocks when you get out of it and touch something gounded. But that’s another post for another time.
I’ve found the vinegar based Windex helps. You’d probably need to clean it multiple times, though.
No matter what windshield cleaner I use, the film comes back. I think it’s our modern, pollution-filled life. I’m not sure there is a way to eliminate this problem. I wish there were, but I haven’t found it yet.
Add to the list: outgassing of all the plastic in the car’s interior, especially the dashboard if you don’t use a sunshade. Those volatile plasticizers can outgas for years.
If it’s equally heavy on the rear window, and there’s very little on the side windows, I’d guess that it’s not coolant (heater core leak). Have you noticed any sweet smell that you can’t account for?
It’s gas-out of interior pieces and you cannot stop it. Just clean it often. I have heard it is not as bad if a window is kept cracked.
You didn’t say anything about your car. The newer it is, the more outgassing occurs. It’s the plasticizers in the dash and rear deck that cause the problem. As time goes by, it will decrease, but never stop. If it does, your dash board will crack soon.
If you use a heat screen when you park the car, you can keep the car plasticizers from messing up your windows. But if the screen is plastic, it will outgas, too. You might look for one with aluminum foil on the window side.