How to De-Ice Your Car Safely Without Damaging It
To de-ice your car safely, use a proper ice scraper and a de-icer spray, and let the engine, heater and demister warm the glass from inside. Never pour hot or boiling water on a frozen windscreen, as the sudden temperature change can crack the glass. Always clear every window, mirror and light before setting off.
Never use hot water
It is tempting to throw a kettle of hot water over a frozen windscreen, but it is one of the most expensive winter mistakes. The sudden temperature change can crack or shatter the glass, especially if there is already a small chip.
Even if the glass survives, the water quickly refreezes, leaving you worse off and possibly icing up the wipers and locks. Stick to proper de-icing methods, which are quicker and safer in the end.
The right tools
A few cheap items make winter mornings much easier and protect your car.
- A proper ice scraper, not a CD case, credit card or knife that can scratch.
- A de-icer spray to loosen ice quickly.
- A soft brush for clearing snow without scratching.
Keep these in the car so you are never caught out on a frosty morning, and a spare scraper in the house for when the doors are iced shut.
Let the car help
Start the engine and set the heater to the windscreen with the air conditioning on, which dries the air and clears mist faster. The heated rear screen and mirrors, if fitted, will clear themselves while you scrape the front.
Do not leave the car running unattended to defrost while you go back inside. It is an insurance risk if the car is stolen, and on a public road, leaving an unattended engine running is an offence. Stay with the car while it warms up.
Frozen locks, wipers and doors
Ice does not just form on the glass. Door seals can freeze shut, so easing the door rather than yanking it avoids tearing the rubber. A frozen lock can be freed with a proper de-icer or by gently warming the key, never by forcing it.
Crucially, never use the wipers on a frozen screen, as the blades can tear or the motor can be damaged trying to move stuck wipers. Make sure the wipers are free and the screen is clear before switching them on, and check they were not left in the raised position overnight.
Preventing ice in the first place
A little prevention saves time. On nights when frost is forecast, a windscreen cover or even an old sheet stops ice forming on the glass, so you simply lift it off in the morning.
Keeping your screenwash topped up with a winter mix that will not freeze means you can clear salt and grime once moving, and parking facing away from the prevailing wind or under cover helps too. These small steps turn a ten-minute scrape into a quick getaway.
Clear everything before you drive
It is an offence to drive without a clear view, so clear the whole windscreen and all windows, not just a small patch. Also clear the mirrors, lights, number plates and any snow on the roof.
Snow left on the roof can slide down over the windscreen when you brake, or fly onto the car behind. Taking a couple of extra minutes to clear everything keeps you legal and safe, and while the engine warms is a good moment to check the screenwash is topped up.
Frequently Asked Questions
Can I use hot water to de-ice my windscreen?
No. Pouring hot or boiling water on frozen glass can crack or shatter it because of the rapid temperature change, especially if there is an existing chip. The water also refreezes quickly. Use a proper scraper and de-icer spray, and let the heater warm the glass from inside.
Is it illegal to leave my car running to defrost?
On a public road, leaving an unattended engine running is an offence, and it can invalidate your insurance if the car is stolen while idling on the driveway. Stay with the car while it defrosts, and use a scraper and de-icer to speed things up safely.
Do I have to clear snow off the whole car?
Yes. You must have a clear view from all windows, and your lights and number plates must be visible, so clear them all. Also remove snow from the roof, as it can slide onto your windscreen when braking or fly onto other vehicles, both of which are dangerous.
Why should I not use the wipers on a frozen screen?
If the blades are frozen to the glass, switching the wipers on can tear the rubber or burn out the wiper motor as it strains against the ice. Always clear the screen and make sure the wipers are free first, and check they were not left raised and frozen overnight.
How can I stop my windscreen freezing overnight?
On frosty nights, cover the windscreen with a proper cover or an old sheet so ice forms on that instead of the glass, then simply lift it off in the morning. Parking under cover or facing away from the wind helps too, saving you a cold scrape before work.
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