Expert advice: Defrosting cars – all you need to know

Defrosting cars

Iced up car windows are all too familiar at this time of year

Defrosting cars is something we all have to do at some point in the year. Although it sounds simple and should be relatively straightforward there are still some dos and don’ts. Here are my top tips to ensure you defrost your car and get going, even in the toughest conditions.

How to defrost your car

The most effective way of defrosting cars’ windows is still with a scraper. It’s always best to use one that’s designed for the job. I know people who swear by credit cards and even old CD cases. The danger with these is they may scratch the screen. A proper ice scraper will allow you to shift the ice quickly and effectively. You can also get de-icer sprays. These are an easy way of doing the job but they’re expensive.

How not to de-ice your car

Don’t try to de-ice your windows by running your windscreen wipers. All you’ll do is cause excessive wear to the blades. And it’ll all be in vain because it won’t shift the ice anyway. Don’t pour boiling water over your windscreen either. It will certainly be very effective at melting the ice. But it’s also a very effective way of causing your screen to crack. If you’ve got a small chip or some damage that you may not have noticed, the boiling water will get into it and the sudden expansion will turn that tiny chip into a rapidly spreading crack. Finally, I read a hack somewhere that involved getting an old plant sprayer and putting a salt water mix in it. I’m sure this works a treat but salt is highly corrosive so your paintwork won’t thank you for it.

Defrosting cars

Spray de-icers are very effective but they can be pricey

De-ice all the windows

You wouldn’t believe how many people we see driving around looking through portholes scraped in the ice. Hazards come at us from all angles when we’re on the road. It’s important that we can see all around us, so make sure you clear the ice from the side windows as well as the entire windscreen.

Defrosting cars: Watch out there’s a thief about

There have been some high-profile cases recently where drivers have started their engines in the road or on the drive. They’ve then gone back inside for a nice hot drink. In the meantime an opportunist has come along, jumped in and driven off. Of course just because the car is there with the keys in and the engine running doesn’t make what the thief does right. But it does make the car fair game. What’s more, insurers are within their rights not to pay out because they can argue the drivers haven’t taken sufficient care of their possessions.

If it’s really cold…

When the thermometer really does drop below zero, locks can freeze up. One way of thawing them is to boil a kettle, leave it to cool for 10 minutes, then pour it over the lock. Parking brakes can stick on too. This is because moisture freezes on the surface of the metal components in the mechanism housed inside the back wheels. If you can, pour a kettle of hot water through the spokes of your rear wheels to free it.

And if you drive a diesel

Diesel engines can be difficult to start in the winter because diesel is more susceptible to cold weather than petrol. Diesel relies on the fuel being compressed in the cylinder and the heat this generates to ignite. But when an engine is very cold, the engine absorbs that heat, making it difficult for the fuel to burn. To get over this, diesels have things called glow plugs. These ignite the fuel even when conditions are freezing cold.

Dashboard warning light for diesel glow plugs or engine management systemFirst thing’s first: when you turn the ignition on, an orange light with a symbol like a curly wire will appear on the dash (left). This light indicates that the glow plugs are heating up. When the light goes out, they’re hot enough to ignite the fuel. When you turn the key the engine should fire easily.

If starting the engine is still difficult in the cold, it might be sensible to take the car in for a service. A new fuel filter may well cure the problem.

self-driving carsNick Reid is a fellow of the Institute of the Motor Industry and head of transformation at Green Flag

One comment on “Expert advice: Defrosting cars – all you need to know

  1. Zoop January 2, 2017 7:01 am

    You can buy isopropyl alcohol (IPA) very cheaply and use a mist spray, or simply buy your IPA in such a container. See ebay for examples.
    This when sprayed lightly on even thick ice, softens it rapidly and makes sraping easy.
    It is the primary ingredient in de-icer and has the advantages of doing little or no harm to your car plus removes grease and similar films from inside and outside surfaces.
    1ltr food grade (99.999%) IPA @ <£7 lasts me over a year and I use it to clean my spectacles, glass surfaces and other workshop uses.
    It is flammable and slightly toxic so google it before you start splashing it everywhere so you know what you are doing.
    Don't confuse IPA with India Pale Ale, which doesn't work that well as de-icer. :-\

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