Dear Tom and Ray:

Last year we bought our teenage son a 1989 Acura Legend coupe. It has been a great car, even though it's pushing 140,000 miles now. We've had to repair a few things here and there, but there is one thing that has me scratching my head. It seems that no matter how much we clean the windows, they become hazy within a few days. The windshield is the biggest problem, especially at night, since the haze makes it impossible to see when there is oncoming traffic. I had the windshield replaced, thinking it was just old and pitted, and that perhaps the safety glass film was failing. The new windshield was brilliant, but within a few days it was foggy again. The haze is on the inside, so I have three possible ideas: (1) My teenage son's oily skin is somehow shape-shifting onto the windows. (2) He smokes a pack of cigarettes while going back and forth to school every day with the windows rolled up. (3) The old upholstery and cheap seat covers are creating some kind of weird gas that clouds the windows. Since my son takes three showers a day and he never smells like smoke, ideas 1 and 2 are out. Do you think it could be No. 3?

-- Wade

TOM: Sure. Usually, vinyl outgassing is at its worst when the car is new. So, at 140,000 miles it's usually over and done with, and those toxic molecules are already lodged in your brain.

RAY: But you mention "cheap seat covers." If they're cheap vinyl seat covers, they could be sublimating toxic gases and leaving the residue on the inside of your windshield.

TOM: The other possibility is that your heater core is leaking. If the heater core has a hole in it, the haze on your windshield could be a thin film of coolant.

RAY: If it's coolant, it would have certain characteristics. It would be greasy to the touch. It would smell sweet. And it would likely be thicker at the bottom of the windshield, near where the vents are.

TOM: So try a couple of experiments. Try removing the seat covers for a week, and see what happens. If that fixes it, your son may need to go commando -- without his seat covers.

RAY: And check the consistency and smell of the windshield grime and its distribution pattern to see if it's coolant.

TOM: If it is coolant, the solution will involve increasing your son's allowance so he can pay you back over time for a new heater core. Good luck, Wade.