How to Deice Your Car’s Windshield

One of the more bothersome challenges of winter is removing ice from your car’s windshield on frosty mornings. Here are some tips from AAA on how to prevent and remove windshield ice.

The adage that an ounce of prevention is worth a pound of cure definitely holds true when it comes to ice on vehicle windshields. You never have to remove something that is not there in the first place, which means the most effective way to prevent ice on a windshield is obviously to park your car in a garage. Even a covered carport can help reduce ice formation in some situations.

If sheltered parking is not an option, covering your windshield will work nearly as well. Use a tarp, large towel or old sheet folded as necessary. Hold the cover in place using the wiper blades, weights, magnets, or some other method, so it will not blow off. Auto parts stores sell windshield covers that typically have magnets built in to help hold them in place. Note that a cover may scratch paint if the finish is dirty, or it moves about in the wind. Also, windshield covers are best used when little or no snowfall is expected; heavy snow can make removing a cover difficult.

To help in ice prevention and removal, some do-it-yourselfers soak cloth windshield covers in a solution of one tablespoon salt to one quart water. The damp cover can be stored in a plastic bag or container between uses.

Commercial spray-on ice and frost “shield” solutions are also available to pretreat the windshield, although they can cost up to $15 per quart. In addition, some ice prevention products contain ethylene glycol, which is poisonous to pets if swallowed. Other do-it-yourselfers often use a homemade windshield pretreatment, consisting of three parts white vinegar to one part water. The solution is applied with a spray bottle the evening before and then wiped off. Leaving the liquid on the glass is ineffective because its freezing point is just barely lower than that of water, and some glass professionals caution that extended exposure to liquid vinegar might cause micro-pitting of the windshield glass.

Before the weather turns cold, fill your automobile’s windshield washer reservoir with winter fluid or a “deicer” solution that will not freeze and can aid in ice removal. Be sure to operate the washers long enough to flush any summer solution from the lines.

When snow or freezing weather is expected, fold the wiper arms up off the glass or place small pieces of wood (or other objects) under the wiper arms to hold the rubber blades off the windshield. This will prevent them from freezing to the glass. The use of one-piece beam-type wiper blades or rubber encased winter wipers will minimize snow and ice buildup on the blades and help speed the removal of both.

To remove ice from a windshield, follow these simple steps:

1. Start the engine
2. Set the heater to defrost
3. Adjust the airflow to recirculate
4. Move the temperature control to full heat

If your car has an automatic climate control system, simply set it to defrost. If your car is one ofthe few with an optional electrically heated windshield, turn it on to rapidly clear ice from the glass.

If desired, apply a commercial glass deicer spray to the windshield. These products generally contain methanol, which is the best form of alcohol for deicing. However, like pretreatment sprays, they tend to cost up to $15 per quart and may contain pet-hazardousethylene glycol.

Some do-it-yourselfers use a homemade deicing solution made of one part isopropyl (rubbing) alcohol and two parts water. The isopropyl alcohol sold in stores ranges from 50 to 90 percent purity. Higher purity provides a lower freezing point and better deicing capability. A few drops of dish soap added to the mixture will act as a surfactant to help coat the ice more evenly. Apply the solution with a spray bottle and, if practical, store it indoors so the added warmth can aid the deicing process. Alcohol-based deicing mixtures freeze at around 5 degrees Fahrenheit versus 32 degrees for water.

As the ice begins to melt, use a plastic scraper, the windshield wipers, a rubber squeegee or a soft bristle brush to remove it from the glass.

Never use metal scrapers, which can scratch the glass and damage wiper blades. Another no-no is hot water, which can crack glass by causing thermal shock and result in an expensive auto glass repair. For the same reason, never try to melt ice with any type of torch. Finally, tapping on the ice with a ball-peen hammer or other tool in an attempt to break it up is just asking for a windshield replacement.

It can be tempting to remove the least amount of ice necessary before driving off on a frigid winter morning. However, the proper procedure is to remove ice and snow from all glass on your vehicle. If you cannot see clearly out of the car in every direction, you are driving in an unsafe manner and your odds of being involved in a collision increase. In order to avoid bodily injury or a costly car repair, it is best to play it safe and remove all snow and ice. In addition, at least 11 states have laws that require snow and ice removal before driving a vehicle. In Minnesota, drivers are required to remove all ice and snow from all vehicle windows before driving - including the sides.

Vinegar-based pretreatments, alcohol-based deicing solutions and dishwashing soap are not directly harmful to your vehicle’s paint. However, they do remove car wax and, over time, will leave the finish exposed to the elements and corrosive chemicals such as road salts. Windshield covers soaked in a saltwater solution pose similar concerns. If you use windshield pretreatments or deicers on a regular basis, keep in mind the need for total car care and periodically wash and rewax any affected areas of the car as weather permits.

AAA recommends that you plan ahead for vehicle service by finding an auto repair shop and technician you can trust before you need them. AAA.com/Repair provides information on nearly 7,000 approved Auto Repair facilities that have met AAA’s high standards for appearance, technician training and certification, insurance coverage and customer satisfaction. AAA regularly inspects every Approved Auto Repair facility and surveys its customers to ensure ongoing performance. In addition, AAA members receive special benefits that include auto repair discounts, an extended 24-month/24,000-mile parts and labor warranty, and AAA assistance in resolving repair-related issues.