Why does the windshield feel oily and not clean when wiped?
4 Answers
The windshield feels oily and not clean when wiped because exhaust fumes form an oily film on the glass, which cannot be cleaned by the wipers alone. Cleaning the glass: Wet the windshield with water, apply toothpaste to the left half, scrub the windshield with a sponge, rinse with clean water, then use dishwashing liquid to clean the right half of the windshield, scrub with a sponge, and rinse with clean water. Replacing the wipers: Generally, when the glass is not clean, the reason can be attributed to the wipers. Or the glass itself is dirty. During driving, dust in the air and exhaust fumes from the vehicle form an oily film, which cannot be cleaned by the wipers alone. At this time, it is necessary to use glass cleaner or toothpaste for cleaning, scrubbing with a sponge in a circular motion with a little force.
I've encountered the same issue. Oil film on the windshield is mostly caused by the accumulation of various pollutants on the road. Especially when driving in the city, unburned hydrocarbons from the exhaust of vehicles in front can adhere to the glass, along with tree resin, insect remains, or bird droppings if parked under trees. Over time, these form an oily film layer. Additionally, using low-quality glass cleaners during car washes or having body ceramic coating liquid splashed onto the glass can also cause this. To completely solve the problem, first purchase a specialized glass degreaser and use it with a sponge to scrub in circular motions with some force, focusing on the driver's line of sight area. When parking, try to avoid areas near kitchen exhaust vents or barbecue stalls. Avoid using regular soapy water to clean the glass during car washes; instead, opt for a neutral glass cleaner. Performing a degreasing treatment every two to three months can effectively prevent this issue.
The windshield wipers aren't cleaning properly and leave an oily sheen. I suspect the wiper blades themselves might be partly to blame. When the rubber strips age and harden, they not only fail to clean effectively but can actually make the glass more oily. My car had this issue last winter, and I later discovered that the windshield surface had accumulated significant oil residue, particularly noticeable in the areas where the wiper arms move up and down. These oily contaminants come from various sources, such as industrial dust in the air, tree sap, or wax residue from the towels used at car washes to wipe the glass. It's best to first check if the wiper rubber strips are cracked or deformed - replace them promptly if they've aged. Removing oil film is simple: mix white kitchen vinegar with water in a 1:2 ratio, spray it on the glass, let it sit for five minutes, then wipe clean with a microfiber cloth. Finally, rinse with clean water for excellent results.
I deeply understand the issue of oily film on the windshield, especially when driving at night in the rain. It is mainly caused by the accumulation of environmental pollutants, such as black smoke emitted by trucks on highways, tree sap dripping from trees in open-air parking lots, and even car wax accidentally applied to the glass during waxing. Last week, I used a specialized test method to verify the oily film: pour water on the dry glass, and if the water droplets do not gather but spread out to form a sheet-like water mark, it indicates the presence of an oily film. When treating it, use clay bar with car shampoo to scrub the glass in circular motions, being careful not to damage the glass with steel wool. For daily maintenance, it is recommended to avoid frequently using windshield washer fluid to spray and wipe, as it can spread the oily film evenly and further impair visibility.
