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Should I Pour Hot Water on My Icy Windshield? Debunking Winter Car Care Myths

Definitely don't do that! Blast the defroster or try a glass deicer.

by Chaya Milchtein
November 29, 2019 | Living

Lots of people have deep-seated fears of car failure, and the repairs that follow, and winter can make it all feel a little more real.

Maybe your parents or some other older person has told you what to do and not do with a car when it's cold out. Sometimes, you'll get advice from one person that conflicts with advice from another.

Debunking winter car care myths means more than just saying they aren’t true, since most of them have some element of truth. That truth makes them more believable.

By understanding the truth behind them, you can better understand how to maintain your car this winter.

Myth: Warm up your car before driving

Until the mid 1990s, vehicles were made with carburetors that required users to warm up their vehicles before taking off on cold winter days.

Illustration of a yellow car covered in snow. Living Rewire PBS Winter car care
Nothing like good old fashioned elbow grease to take care of this! Leaving your car running to melt the snow isn't good for the environment — and it's possibly illegal where you live.

These days, while many mechanics still recommend it, it’s actually unnecessary and bad for the environment. However, if your windshield is covered in ice, you might need to run the defroster to be able to see the road and drive safely.

Chris Mooney wrote about this myth extensively for The Washington Post. He pointed out that cold places like Minneapolis actually have laws preventing you from idling for extended periods because of the harm you are doing to the environment. In Minneapolis, you can only idle your car for three minutes per hour.

Myth: Deflate your tires to get better traction

This is a dangerous tactic to get what will amount to very little additional traction in snow conditions. While it will make the footprint of the tire wider, technically providing you with a little more gripping power, it would only help (if it helps at all) when there's a lot of snow on the ground.

Let’s say you're leaving your driveway, your tires deflated to 15 PSI, and you drive through your snowy subdivision. Now you're on the main road, which has been plowed. Those deflated tires have become extremely dangerous; you've significantly increased the chance of a blowout.

Instead, do this:

If you're often driving on unplowed snowy roads, consider investing in winter, or snow, tires.

Myth: Four- and all-wheel drive makes driving in the snow easy

Four-wheel drive or all-wheel drive does help you propel forward and drive through snow, but it doesn’t necessarily make it safer. It’s most helpful when you are trying to get out of a snowed-in parking spot or unplowed side road.

What doesn’t it do? It won’t help you stop the car. If you are rolling along, feeling invincible and need to come to a sudden stop, your four-wheel drive won’t help you stop or stay in control of your vehicle on snowy or icy road.

Four-wheel drive is definitely helpful. Just remember driving safely means keeping a safe distance from the car in front of you, and being able to control not just the forward momentum of your car, but also how your car behaves when you try to stop.

Myth: Get your car winterized

Getting your car winterized sounds good, right? You’re doing your due diligence to take good care of your car in the wintertime.

Wrong. What some mechanics call winterizing is a service that is frankly unnecessary for your car. It includes replacing your coolant, thermostat and gasket. It won’t hurt, but it’s money you probably don’t need to be spending.

Instead, do this:

Check your owner's manual to learn how often your car actually needs the coolant replaced.

Get a checkup. Make sure your brakes and tires are inspected before winter. Making sure you have the best stopping power possible should be at the top of your priority list before winter.

Check your washer fluid and wiper blades. Wiper blades are not typically high on our car maintenance priority list. But, in the winter, ice and snow can make seeing through your windshield really hard and good winter blades will help you see clearly.

Using winter-grade washer fluid with deicer can also be super helpful. Watered-down fluid or fluid that can't withstand your lowest temperatures will freeze and expand, and could damage the plastic container that holds it.

Get your battery tested. If you've ever left the grocery store in winter to find that your car won't start, you know why this is an important step. Your mechanic can check your battery during an oil change or pre-winter checkup. Stores like AutoZone will test it for free, as well.

[ICYMI: When Do I Really Need to Take My Car to the Shop?]

Myth: Keep your gas tank at least half full

This one isn’t right or wrong. Some theorize that condensation can develop inside the fuel system which could cause issues if your tank is more than half empty. However, this is highly unlikely.

The main reason to keep keep your fuel level high is in case of an emergency. If you get stranded and need to keep your car running for heat, having enough fuel is crucial. A higher fuel level can also help your car start easier on those really cold mornings.

Myth: Melt the ice on your windshield by pouring hot water on it

Since the windshield is freezing cold and the water is boiling hot, doing this can actually cause the glass to go into thermal shock, most often making the glass crack. Definitely don’t try this, no matter how much of a rush you're in.

Instead, do this:

Put the heat on the highest setting and turn on the defroster. This does take time and patience, and some elbow grease with a scraper if you're in a hurry. But if you can wait for the ice to melt a bit, scraping it away will be easy.

Commercial glass deicer is a faster-working option. But it's pretty pricey, so most people go for the first option.

Not a myth: Develop a relationship with a mechanic

Here's the bottom line: When it comes to winter car care, and car repairs and maintenance in general, the key is to develop a relationship with a mechanic.

Having someone you trust to advise you on repairs and answer your questions about car care will help you make sure your car is running at its best.

Chaya Milchtein
Chaya Milchtein writes about cars, culture and queer life. She empowers people to do the impossible and be authentically themselves. Follow her @mechanicfemme.
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